Search Results
Showing 1-20 of about 138 results.
A Search for Companions via Direct Imaging in the DSHARP Planet-forming DisksJorquera, SebastianPérez, Laura M.Chauvin, GaëlBenisty, MyriamZhu, ZhaohuanIsella, AndreaHuang, JaneRicci, LucaAndrews, Sean M.Zhang, ShangjiaCarpenter, John M.Kurtovic, Nicolás T.Birnstiel, TilmanDOI: info:10.3847/1538-3881/abd40dv. 161146
Jorquera, Sebastian, Pérez, Laura M., Chauvin, Gaël, Benisty, Myriam, Zhu, Zhaohuan, Isella, Andrea, Huang, Jane, Ricci, Luca, Andrews, Sean M., Zhang, Shangjia, Carpenter, John M., Kurtovic, Nicolás T., and Birnstiel, Tilman. 2021. "A Search for Companions via Direct Imaging in the DSHARP Planet-forming Disks." The Astronomical Journal 161:146. https://doi.org/10.3847/1538-3881/abd40d
ID: 159329
Type: article
Authors: Jorquera, Sebastian; Pérez, Laura M.; Chauvin, Gaël; Benisty, Myriam; Zhu, Zhaohuan; Isella, Andrea; Huang, Jane; Ricci, Luca; Andrews, Sean M.; Zhang, Shangjia; Carpenter, John M.; Kurtovic, Nicolás T.; Birnstiel, Tilman
Abstract: The "Disk Substructures at High Angular Resolution Project" (DSHARP) has revealed an abundance and ubiquity of rings and gaps over a large sample of young planet-forming disks, which are hypothesized to be induced by the presence of forming planets. In this context, we present the first attempt to directly image these young companions for 10 of the DSHARP disks, by using the NaCo/VLT high-contrast observations in L' band instrument and angular differential imaging techniques. We report the detection of a point-like source candidate at 1"1 (174.9 au) for RU Lup and at 0"42 (55 au) for Elias 24. In the case of RU Lup, the proper motion of the candidate is consistent with a stationary background contaminant, based on the astrometry derived from our observations and available archival data. For Elias 24 the point-like source candidate is located in one of the disk gaps at 55 au. Assuming that it is a planetary companion, our analysis suggests a mass ranging from 0.5MJ up to 5MJ, depending on the presence of a circumplanetary disk and its contribution to the luminosity of the system. However, no clear confirmation is obtained at this stage, and follow-up observations are mandatory to verify that the proposed source is physical, comoving with the stellar host, and associated with a young massive planet sculpting the gap observed at 55 au. For all the remaining systems, the lack of detections suggests the presence of planetary companions with masses lower than 5MJ, based on our derived mass detection limits. This is consistent with predictions of both hydrodynamical simulations and kinematical signatures on the disk and allows us to set upper limits on the presence of massive planets in these young disks.
Type: article
Authors: Jorquera, Sebastian; Pérez, Laura M.; Chauvin, Gaël; Benisty, Myriam; Zhu, Zhaohuan; Isella, Andrea; Huang, Jane; Ricci, Luca; Andrews, Sean M.; Zhang, Shangjia; Carpenter, John M.; Kurtovic, Nicolás T.; Birnstiel, Tilman
Abstract: The "Disk Substructures at High Angular Resolution Project" (DSHARP) has revealed an abundance and ubiquity of rings and gaps over a large sample of young planet-forming disks, which are hypothesized to be induced by the presence of forming planets. In this context, we present the first attempt to directly image these young companions for 10 of the DSHARP disks, by using the NaCo/VLT high-contrast observations in L' band instrument and angular differential imaging techniques. We report the detection of a point-like source candidate at 1"1 (174.9 au) for RU Lup and at 0"42 (55 au) for Elias 24. In the case of RU Lup, the proper motion of the candidate is consistent with a stationary background contaminant, based on the astrometry derived from our observations and available archival data. For Elias 24 the point-like source candidate is located in one of the disk gaps at 55 au. Assuming that it is a planetary companion, our analysis suggests a mass ranging from 0.5MJ up to 5MJ, depending on the presence of a circumplanetary disk and its contribution to the luminosity of the system. However, no clear confirmation is obtained at this stage, and follow-up observations are mandatory to verify that the proposed source is physical, comoving with the stellar host, and associated with a young massive planet sculpting the gap observed at 55 au. For all the remaining systems, the lack of detections suggests the presence of planetary companions with masses lower than 5MJ, based on our derived mass detection limits. This is consistent with predictions of both hydrodynamical simulations and kinematical signatures on the disk and allows us to set upper limits on the presence of massive planets in these young disks.
Dynamical Masses and Stellar Evolutionary Model Predictions of M StarsPegues, JamilaCzekala, IanAndrews, Sean M.Öberg, Karin I.Herczeg, Gregory J.Bergner, Jennifer B.Ilsedore Cleeves, L.Guzmán, Viviana V.Huang, JaneLong, FengTeague, RichardWilner, David J.DOI: info:10.3847/1538-4357/abd4ebv. 90842
Pegues, Jamila, Czekala, Ian, Andrews, Sean M., Öberg, Karin I., Herczeg, Gregory J., Bergner, Jennifer B., Ilsedore Cleeves, L., Guzmán, Viviana V., Huang, Jane, Long, Feng, Teague, Richard, and Wilner, David J. 2021. "Dynamical Masses and Stellar Evolutionary Model Predictions of M Stars." The Astrophysical Journal 908:42. https://doi.org/10.3847/1538-4357/abd4eb
ID: 159623
Type: article
Authors: Pegues, Jamila; Czekala, Ian; Andrews, Sean M.; Öberg, Karin I.; Herczeg, Gregory J.; Bergner, Jennifer B.; Ilsedore Cleeves, L.; Guzmán, Viviana V.; Huang, Jane; Long, Feng; Teague, Richard; Wilner, David J.
Abstract: In this era of Gaia and ALMA, dynamical stellar mass measurements, derived from spatially and spectrally resolved observations of the Keplerian rotation of circumstellar disks, provide benchmarks that are independent of observations of stellar characteristics and their uncertainties. These benchmarks can then be used to validate and improve stellar evolutionary models, the latter of which can lead to both imprecise and inaccurate mass predictions for pre-main-sequence, low-mass (≤0.5 M⊙) stars. We present the dynamical stellar masses derived from disks around three M stars (FP Tau, J0432+1827, and J1100-7619) using ALMA observations of 12CO (J = 2-1) and 13CO (J = 2-1) emission. These are the first dynamical stellar mass measurements for J0432+1827 and J1100-7619 (0.192 ± 0.005 M⊙ and 0.461 ± 0.057 M⊙, respectively) and the most precise measurement for FP Tau (0.395 ± 0.012 M⊙). Fiducial stellar evolutionary model tracks, which do not include any treatment of magnetic activity, agree with the dynamical stellar mass measurement of J0432+1827 but underpredict the mass by ∼60% for FP Tau and by ∼80% for J1100-7619. Possible explanations for the underpredictions include inaccurate assumptions of stellar effective temperature, undetected binarity for J1100-7619, and that fiducial stellar evolutionary models are not complex enough to represent these stars. In the former case, the stellar effective temperatures would need to be increased by amounts ranging from ∼40 to ∼340 K to reconcile the fiducial stellar evolutionary model predictions with the dynamically measured masses. In the latter case, we show that the dynamical masses can be reproduced using results from stellar evolutionary models with starspots, which incorporate fractional starspot coverage to represent the manifestation of magnetic activity. Folding in low-mass M stars from the literature and assuming that the stellar effective temperatures are imprecise but accurate, we find tentative evidence of a relationship between fractional starspot coverage and observed effective temperature for these young, cool stars.
Type: article
Authors: Pegues, Jamila; Czekala, Ian; Andrews, Sean M.; Öberg, Karin I.; Herczeg, Gregory J.; Bergner, Jennifer B.; Ilsedore Cleeves, L.; Guzmán, Viviana V.; Huang, Jane; Long, Feng; Teague, Richard; Wilner, David J.
Abstract: In this era of Gaia and ALMA, dynamical stellar mass measurements, derived from spatially and spectrally resolved observations of the Keplerian rotation of circumstellar disks, provide benchmarks that are independent of observations of stellar characteristics and their uncertainties. These benchmarks can then be used to validate and improve stellar evolutionary models, the latter of which can lead to both imprecise and inaccurate mass predictions for pre-main-sequence, low-mass (≤0.5 M⊙) stars. We present the dynamical stellar masses derived from disks around three M stars (FP Tau, J0432+1827, and J1100-7619) using ALMA observations of 12CO (J = 2-1) and 13CO (J = 2-1) emission. These are the first dynamical stellar mass measurements for J0432+1827 and J1100-7619 (0.192 ± 0.005 M⊙ and 0.461 ± 0.057 M⊙, respectively) and the most precise measurement for FP Tau (0.395 ± 0.012 M⊙). Fiducial stellar evolutionary model tracks, which do not include any treatment of magnetic activity, agree with the dynamical stellar mass measurement of J0432+1827 but underpredict the mass by ∼60% for FP Tau and by ∼80% for J1100-7619. Possible explanations for the underpredictions include inaccurate assumptions of stellar effective temperature, undetected binarity for J1100-7619, and that fiducial stellar evolutionary models are not complex enough to represent these stars. In the former case, the stellar effective temperatures would need to be increased by amounts ranging from ∼40 to ∼340 K to reconcile the fiducial stellar evolutionary model predictions with the dynamically measured masses. In the latter case, we show that the dynamical masses can be reproduced using results from stellar evolutionary models with starspots, which incorporate fractional starspot coverage to represent the manifestation of magnetic activity. Folding in low-mass M stars from the literature and assuming that the stellar effective temperatures are imprecise but accurate, we find tentative evidence of a relationship between fractional starspot coverage and observed effective temperature for these young, cool stars.
Observations of Protoplanetary Disk StructuresAndrews, Sean M.DOI: info:10.1146/annurev-astro-031220-010302v. 58483–528
Andrews, Sean M. 2020. "Observations of Protoplanetary Disk Structures." Annual Review of Astronomy and Astrophysics 58:483– 528. https://doi.org/10.1146/annurev-astro-031220-010302
ID: 158881
Type: article
Authors: Andrews, Sean M.
Abstract: The disks that orbit young stars are the essential conduits and reservoirs of material for star and planet formation. Their structures, meaning the spatial variations of the disk physical conditions, reflect the underlying mechanisms that drive those formation processes. Observations of the solids and gas in these disks, particularly at high resolution, provide fundamental insights on their mass distributions, dynamical states, and evolutionary behaviors. Over the past decade, rapid developments in these areas have largely been driven by observations with the Atacama Large Millimeter/submillimeter Array (ALMA). This review highlights the state of observational research on disk structures, emphasizing the following three key conclusions that reflect the main branches of the field: Relationships among disk structure properties are also linked to the masses, environments, and evolutionary states of their stellar hosts. There is clear, qualitative evidence for the growth and migration of disk solids, although the implied evolutionary timescales suggest the classical assumption of a smooth gas disk is inappropriate. Small-scale substructures with a variety of morphologies, locations, scales, and amplitudes-presumably tracing local gas pressure maxima-broadly influence the physical and observational properties of disks.The last point especially is reshaping the field, with the recognition that these disk substructures likely trace active sites of planetesimal growth or are the hallmarks of planetary systems at their formation epoch.
Type: article
Authors: Andrews, Sean M.
Abstract: The disks that orbit young stars are the essential conduits and reservoirs of material for star and planet formation. Their structures, meaning the spatial variations of the disk physical conditions, reflect the underlying mechanisms that drive those formation processes. Observations of the solids and gas in these disks, particularly at high resolution, provide fundamental insights on their mass distributions, dynamical states, and evolutionary behaviors. Over the past decade, rapid developments in these areas have largely been driven by observations with the Atacama Large Millimeter/submillimeter Array (ALMA). This review highlights the state of observational research on disk structures, emphasizing the following three key conclusions that reflect the main branches of the field: Relationships among disk structure properties are also linked to the masses, environments, and evolutionary states of their stellar hosts. There is clear, qualitative evidence for the growth and migration of disk solids, although the implied evolutionary timescales suggest the classical assumption of a smooth gas disk is inappropriate. Small-scale substructures with a variety of morphologies, locations, scales, and amplitudes-presumably tracing local gas pressure maxima-broadly influence the physical and observational properties of disks.The last point especially is reshaping the field, with the recognition that these disk substructures likely trace active sites of planetesimal growth or are the hallmarks of planetary systems at their formation epoch.
An Evolutionary Study of Volatile Chemistry in Protoplanetary DisksBergner, Jennifer B.Öberg, Karin I.Bergin, Edwin A.Andrews, Sean M.Blake, Geoffrey A.Carpenter, John M.Cleeves, L. IlsedoreGuzmán, Viviana V.Huang, JaneJørgensen, Jes K.Qi, ChunhuaSchwarz, Kamber R.Williams, Jonathan P.Wilner, David J.DOI: info:10.3847/1538-4357/ab9e71v. 89897
Bergner, Jennifer B., Öberg, Karin I., Bergin, Edwin A., Andrews, Sean M., Blake, Geoffrey A., Carpenter, John M., Cleeves, L. Ilsedore, Guzmán, Viviana V., Huang, Jane, Jørgensen, Jes K., Qi, Chunhua, Schwarz, Kamber R., Williams, Jonathan P., and Wilner, David J. 2020. "An Evolutionary Study of Volatile Chemistry in Protoplanetary Disks." The Astrophysical Journal 898:97. https://doi.org/10.3847/1538-4357/ab9e71
ID: 157660
Type: article
Authors: Bergner, Jennifer B.; Öberg, Karin I.; Bergin, Edwin A.; Andrews, Sean M.; Blake, Geoffrey A.; Carpenter, John M.; Cleeves, L. Ilsedore; Guzmán, Viviana V.; Huang, Jane; Jørgensen, Jes K.; Qi, Chunhua; Schwarz, Kamber R.; Williams, Jonathan P.; Wilner, David J.
Abstract: The volatile composition of a planet is determined by the inventory of gas and ice in the parent disk. The volatile chemistry in the disk is expected to evolve over time, though this evolution is poorly constrained observationally. We present Atacama Large Millimeter/submillimeter Array observations of C18O, C2H, and the isotopologues H13CN, HC15N, and DCN toward five Class 0/I disk candidates. Combined with a sample of 14 Class II disks presented in Bergner et al., this data set offers a view of volatile chemical evolution over the disk lifetime. Our estimates of C18O abundances are consistent with a rapid depletion of CO in the first ∼0.5-1 Myr of the disk lifetime. We do not see evidence that C2H and HCN formation are enhanced by CO depletion, possibly because the gas is already quite under-abundant in CO. Further CO depletion may actually hinder their production by limiting the gas-phase carbon supply. The embedded sources show several chemical differences compared to the Class II stage, which seem to arise from shielding of radiation by the envelope (impacting C2H formation and HC15N fractionation) and sublimation of ices from infalling material (impacting HCN and C18O abundances). Such chemical differences between Class 0/I and Class II sources may affect the volatile composition of planet-forming material at different stages in the disk lifetime.
Type: article
Authors: Bergner, Jennifer B.; Öberg, Karin I.; Bergin, Edwin A.; Andrews, Sean M.; Blake, Geoffrey A.; Carpenter, John M.; Cleeves, L. Ilsedore; Guzmán, Viviana V.; Huang, Jane; Jørgensen, Jes K.; Qi, Chunhua; Schwarz, Kamber R.; Williams, Jonathan P.; Wilner, David J.
Abstract: The volatile composition of a planet is determined by the inventory of gas and ice in the parent disk. The volatile chemistry in the disk is expected to evolve over time, though this evolution is poorly constrained observationally. We present Atacama Large Millimeter/submillimeter Array observations of C18O, C2H, and the isotopologues H13CN, HC15N, and DCN toward five Class 0/I disk candidates. Combined with a sample of 14 Class II disks presented in Bergner et al., this data set offers a view of volatile chemical evolution over the disk lifetime. Our estimates of C18O abundances are consistent with a rapid depletion of CO in the first ∼0.5-1 Myr of the disk lifetime. We do not see evidence that C2H and HCN formation are enhanced by CO depletion, possibly because the gas is already quite under-abundant in CO. Further CO depletion may actually hinder their production by limiting the gas-phase carbon supply. The embedded sources show several chemical differences compared to the Class II stage, which seem to arise from shielding of radiation by the envelope (impacting C2H formation and HC15N fractionation) and sublimation of ices from infalling material (impacting HCN and C18O abundances). Such chemical differences between Class 0/I and Class II sources may affect the volatile composition of planet-forming material at different stages in the disk lifetime.
Midplane temperature and outer edge of the protoplanetary disk around HD 163296Dullemond, C. P.Isella, A.Andrews, Sean M.Skobleva, I.Dzyurkevich, N.DOI: info:10.1051/0004-6361/201936438v. 633A137
Dullemond, C. P., Isella, A., Andrews, Sean M., Skobleva, I., and Dzyurkevich, N. 2020. "Midplane temperature and outer edge of the protoplanetary disk around HD 163296." Astronomy and Astrophysics 633:A137. https://doi.org/10.1051/0004-6361/201936438
ID: 155677
Type: article
Authors: Dullemond, C. P.; Isella, A.; Andrews, Sean M.; Skobleva, I.; Dzyurkevich, N.
Abstract: Knowledge of the midplane temperature of protoplanetary disks is one of the key ingredients in theories of dust growth and planet formation. However, direct measurement of this quantity is complicated, and often depends on the fitting of complex models to data. In this paper we demonstrate a method to directly measure the midplane gas temperature from an optically thick molecular line if the disk is moderately inclined. The only model assumption that enters is that the line is very optically thick, specifically in the midplane region where we wish to measure the temperature. Freeze-out of the molecule onto dust grains could thwart this. However, in regions that are expected to be warm enough to avoid freeze-out, this method should work. We apply the method to the CO 2-1 line channel maps of the disk around HD 163296. We find that the midplane temperature between 100 and 400 au drops only mildly from 25 K down to 18 K. While we see no direct evidence of the midplane being optically thin due to strong CO depletion by freeze-out, we cannot rule it out either. The fact that the inferred temperatures are close to the expected CO freeze-out temperature could be an indication of this. Incidently, for the disk around HD 163296 we also find dynamic evidence for a rather abrupt outer edge of the disk, suggestive of outside-in photoevaporation or truncation by an unseen companion.
Type: article
Authors: Dullemond, C. P.; Isella, A.; Andrews, Sean M.; Skobleva, I.; Dzyurkevich, N.
Abstract: Knowledge of the midplane temperature of protoplanetary disks is one of the key ingredients in theories of dust growth and planet formation. However, direct measurement of this quantity is complicated, and often depends on the fitting of complex models to data. In this paper we demonstrate a method to directly measure the midplane gas temperature from an optically thick molecular line if the disk is moderately inclined. The only model assumption that enters is that the line is very optically thick, specifically in the midplane region where we wish to measure the temperature. Freeze-out of the molecule onto dust grains could thwart this. However, in regions that are expected to be warm enough to avoid freeze-out, this method should work. We apply the method to the CO 2-1 line channel maps of the disk around HD 163296. We find that the midplane temperature between 100 and 400 au drops only mildly from 25 K down to 18 K. While we see no direct evidence of the midplane being optically thin due to strong CO depletion by freeze-out, we cannot rule it out either. The fact that the inferred temperatures are close to the expected CO freeze-out temperature could be an indication of this. Incidently, for the disk around HD 163296 we also find dynamic evidence for a rather abrupt outer edge of the disk, suggestive of outside-in photoevaporation or truncation by an unseen companion.
Measuring Turbulent Motion in Planet-forming Disks with ALMA: A Detection around DM Tau and Nondetections around MWC 480 and V4046 SgrFlaherty, KevinHughes, A. MeredithSimon, Jacob B.Qi, ChunhuaBai, Xue-NingBulatek, AlyssaAndrews, Sean M.Wilner, David J.Kóspál, ÁgnesDOI: info:10.3847/1538-4357/ab8cc5v. 895109
Flaherty, Kevin, Hughes, A. Meredith, Simon, Jacob B., Qi, Chunhua, Bai, Xue-Ning, Bulatek, Alyssa, Andrews, Sean M., Wilner, David J., and Kóspál, Ágnes. 2020. "Measuring Turbulent Motion in Planet-forming Disks with ALMA: A Detection around DM Tau and Nondetections around MWC 480 and V4046 Sgr." The Astrophysical Journal 895:109. https://doi.org/10.3847/1538-4357/ab8cc5
ID: 156877
Type: article
Authors: Flaherty, Kevin; Hughes, A. Meredith; Simon, Jacob B.; Qi, Chunhua; Bai, Xue-Ning; Bulatek, Alyssa; Andrews, Sean M.; Wilner, David J.; Kóspál, Ágnes
Abstract: Turbulence is a crucial factor in many models of planet formation, but it has only been directly constrained among a small number of planet- forming disks. Building on the upper limits on turbulence placed in disks around HD 163296 and TW Hya, we present ALMA CO J = 2-1 line observations at ∼0"3 (20-50 au) resolution and 80 ms-1 channel spacing of the disks around DM Tau, MWC 480, and V4046 Sgr. Using parametric models of disk structure, we robustly detect nonthermal gas motions around DM Tau of between 0.25cs and 0.33cs, with the range dominated by systematic effects, making this one of the only systems with directly measured nonzero turbulence. Using the same methodology, we place stringent upper limits on the nonthermal gas motion around MWC 480 (, with the range dominated by systematic effects, making this one of the only systems with directly measured nonzero turbulence. Using the same methodology, we place stringent upper limits on the nonthermal gas motion around MWC 480 (s) and V4046 Sgr () and V4046 Sgr (s). The preponderance of upper limits in this small sample and the modest turbulence levels consistent with dust studies suggest that weak turbulence (α ≲ 10-3) may be a common, albeit not universal, feature of planet-forming disks. We explore the particular physical conditions around DM Tau that could lead this system to be more turbulent than the others.
Type: article
Authors: Flaherty, Kevin; Hughes, A. Meredith; Simon, Jacob B.; Qi, Chunhua; Bai, Xue-Ning; Bulatek, Alyssa; Andrews, Sean M.; Wilner, David J.; Kóspál, Ágnes
Abstract: Turbulence is a crucial factor in many models of planet formation, but it has only been directly constrained among a small number of planet- forming disks. Building on the upper limits on turbulence placed in disks around HD 163296 and TW Hya, we present ALMA CO J = 2-1 line observations at ∼0"3 (20-50 au) resolution and 80 ms-1 channel spacing of the disks around DM Tau, MWC 480, and V4046 Sgr. Using parametric models of disk structure, we robustly detect nonthermal gas motions around DM Tau of between 0.25cs and 0.33cs, with the range dominated by systematic effects, making this one of the only systems with directly measured nonzero turbulence. Using the same methodology, we place stringent upper limits on the nonthermal gas motion around MWC 480 (, with the range dominated by systematic effects, making this one of the only systems with directly measured nonzero turbulence. Using the same methodology, we place stringent upper limits on the nonthermal gas motion around MWC 480 (s) and V4046 Sgr () and V4046 Sgr (s). The preponderance of upper limits in this small sample and the modest turbulence levels consistent with dust studies suggest that weak turbulence (α ≲ 10-3) may be a common, albeit not universal, feature of planet-forming disks. We explore the particular physical conditions around DM Tau that could lead this system to be more turbulent than the others.
Erratum: 'The Disk Substructures at High Angular Resolution Project (DSHARP). II. Characteristics of Annular Substructures' (2018, ApJL, 869, L42)Huang, JaneAndrews, Sean M.Dullemond, Cornelis P.Isella, AndreaPérez, Laura M.Guzmán, Viviana V.Öberg, Karin I.Zhu, ZhaohuanZhang, ShangjiaBai, Xue-NingBenisty, MyriamBirnstiel, TilmanCarpenter, John M.Hughes, A. MeredithRicci, LucaWeaver, ErikWilner, David J.DOI: info:10.3847/2041-8213/aba83bv. 898L57
Huang, Jane, Andrews, Sean M., Dullemond, Cornelis P., Isella, Andrea, Pérez, Laura M., Guzmán, Viviana V., Öberg, Karin I., Zhu, Zhaohuan, Zhang, Shangjia, Bai, Xue-Ning, Benisty, Myriam, Birnstiel, Tilman, Carpenter, John M., Hughes, A. Meredith, Ricci, Luca, Weaver, Erik, and Wilner, David J. 2020. "Erratum: "The Disk Substructures at High Angular Resolution Project (DSHARP). II. Characteristics of Annular Substructures" (2018, ApJL, 869, L42)." The Astrophysical Journal 898:L57. https://doi.org/10.3847/2041-8213/aba83b
ID: 157658
Type: article
Authors: Huang, Jane; Andrews, Sean M.; Dullemond, Cornelis P.; Isella, Andrea; Pérez, Laura M.; Guzmán, Viviana V.; Öberg, Karin I.; Zhu, Zhaohuan; Zhang, Shangjia; Bai, Xue-Ning; Benisty, Myriam; Birnstiel, Tilman; Carpenter, John M.; Hughes, A. Meredith; Ricci, Luca; Weaver, Erik; Wilner, David J.
Type: article
Authors: Huang, Jane; Andrews, Sean M.; Dullemond, Cornelis P.; Isella, Andrea; Pérez, Laura M.; Guzmán, Viviana V.; Öberg, Karin I.; Zhu, Zhaohuan; Zhang, Shangjia; Bai, Xue-Ning; Benisty, Myriam; Birnstiel, Tilman; Carpenter, John M.; Hughes, A. Meredith; Ricci, Luca; Weaver, Erik; Wilner, David J.
A Multifrequency ALMA Characterization of Substructures in the GM Aur Protoplanetary DiskHuang, JaneAndrews, Sean M.Dullemond, Cornelis P.Öberg, Karin I.Qi, ChunhuaZhu, ZhaohuanBirnstiel, TilmanCarpenter, John M.Isella, AndreaMacías, EnriqueMcClure, Melissa K.Pérez, Laura M.Teague, RichardWilner, David J.Zhang, ShangjiaDOI: info:10.3847/1538-4357/ab711ev. 89148
Huang, Jane, Andrews, Sean M., Dullemond, Cornelis P., Öberg, Karin I., Qi, Chunhua, Zhu, Zhaohuan, Birnstiel, Tilman, Carpenter, John M., Isella, Andrea, Macías, Enrique, McClure, Melissa K., Pérez, Laura M., Teague, Richard, Wilner, David J., and Zhang, Shangjia. 2020. "A Multifrequency ALMA Characterization of Substructures in the GM Aur Protoplanetary Disk." The Astrophysical Journal 891:48. https://doi.org/10.3847/1538-4357/ab711e
ID: 156375
Type: article
Authors: Huang, Jane; Andrews, Sean M.; Dullemond, Cornelis P.; Öberg, Karin I.; Qi, Chunhua; Zhu, Zhaohuan; Birnstiel, Tilman; Carpenter, John M.; Isella, Andrea; Macías, Enrique; McClure, Melissa K.; Pérez, Laura M.; Teague, Richard; Wilner, David J.; Zhang, Shangjia
Abstract: The protoplanetary disk around the T Tauri star GM Aur was one of the first hypothesized to be in the midst of being cleared out by a forming planet. As a result, GM Aur has had an outsized influence on our understanding of disk structure and evolution. We present 1.1 and 2.1 mm ALMA continuum observations of the GM Aur disk at a resolution of ∼50 mas (∼8 au), as well as HCO+ J = 3 - 2 observations at a resolution of ∼100 mas. The dust continuum shows at least three rings atop faint, extended emission. Unresolved emission is detected at the center of the disk cavity at both wavelengths, likely due to a combination of dust and free-free emission. Compared to the 1.1 mm image, the 2.1 mm image shows a more pronounced "shoulder" near R ∼ 40 au, highlighting the utility of longer-wavelength observations for characterizing disk substructures. The spectral index α features strong radial variations, with minima near the emission peaks and maxima near the gaps. While low spectral indices have often been ascribed to grain growth and dust trapping, the optical depth of GM Aur's inner two emission rings renders their dust properties ambiguous. The gaps and outer disk (R > 100 au) are optically thin at both wavelengths. Meanwhile, the HCO+ emission indicates that the gas cavity is more compact than the dust cavity traced by the millimeter continuum, similar to other disks traditionally classified as "transitional."
Type: article
Authors: Huang, Jane; Andrews, Sean M.; Dullemond, Cornelis P.; Öberg, Karin I.; Qi, Chunhua; Zhu, Zhaohuan; Birnstiel, Tilman; Carpenter, John M.; Isella, Andrea; Macías, Enrique; McClure, Melissa K.; Pérez, Laura M.; Teague, Richard; Wilner, David J.; Zhang, Shangjia
Abstract: The protoplanetary disk around the T Tauri star GM Aur was one of the first hypothesized to be in the midst of being cleared out by a forming planet. As a result, GM Aur has had an outsized influence on our understanding of disk structure and evolution. We present 1.1 and 2.1 mm ALMA continuum observations of the GM Aur disk at a resolution of ∼50 mas (∼8 au), as well as HCO+ J = 3 - 2 observations at a resolution of ∼100 mas. The dust continuum shows at least three rings atop faint, extended emission. Unresolved emission is detected at the center of the disk cavity at both wavelengths, likely due to a combination of dust and free-free emission. Compared to the 1.1 mm image, the 2.1 mm image shows a more pronounced "shoulder" near R ∼ 40 au, highlighting the utility of longer-wavelength observations for characterizing disk substructures. The spectral index α features strong radial variations, with minima near the emission peaks and maxima near the gaps. While low spectral indices have often been ascribed to grain growth and dust trapping, the optical depth of GM Aur's inner two emission rings renders their dust properties ambiguous. The gaps and outer disk (R > 100 au) are optically thin at both wavelengths. Meanwhile, the HCO+ emission indicates that the gas cavity is more compact than the dust cavity traced by the millimeter continuum, similar to other disks traditionally classified as "transitional."
Large-scale CO Spiral Arms and Complex Kinematics Associated with the T Tauri Star RU LupHuang, JaneAndrews, Sean M.Öberg, Karin I.Ansdell, MeganBenisty, MyriamCarpenter, John M.Isella, AndreaPérez, Laura M.Ricci, LucaWilliams, Jonathan P.Wilner, David J.Zhu, ZhaohuanDOI: info:10.3847/1538-4357/aba1e1v. 898140
Huang, Jane, Andrews, Sean M., Öberg, Karin I., Ansdell, Megan, Benisty, Myriam, Carpenter, John M., Isella, Andrea, Pérez, Laura M., Ricci, Luca, Williams, Jonathan P., Wilner, David J., and Zhu, Zhaohuan. 2020. "Large-scale CO Spiral Arms and Complex Kinematics Associated with the T Tauri Star RU Lup." The Astrophysical Journal 898:140. https://doi.org/10.3847/1538-4357/aba1e1
ID: 157659
Type: article
Authors: Huang, Jane; Andrews, Sean M.; Öberg, Karin I.; Ansdell, Megan; Benisty, Myriam; Carpenter, John M.; Isella, Andrea; Pérez, Laura M.; Ricci, Luca; Williams, Jonathan P.; Wilner, David J.; Zhu, Zhaohuan
Abstract: While protoplanetary disks often appear to be compact and well organized in millimeter continuum emission, CO spectral line observations are increasingly revealing complex behavior at large distances from the host star. We present deep Atacama Large Millimeter/submillimeter Array maps of the J = 2-1 transition of 12CO, 13CO, and C18O, as well as the J = 3-2 transition of DCO+, toward the T Tauri star RU Lup at a resolution of ∼0.3″ (∼50 au). The CO isotopologue emission traces four major components of the RU Lup system: a compact Keplerian disk with a radius of ∼120 au, a non-Keplerian "envelope-like" structure surrounding the disk and extending to ∼260 au from the star, at least five blueshifted spiral arms stretching up to 1000 au, and clumps outside the spiral arms located up to 1500 au in projection from RU Lup. We comment on potential explanations for RU Lup's peculiar gas morphology, including gravitational instability, accretion of material onto the disk, or perturbation by another star. RU Lup's extended non-Keplerian CO emission, elevated stellar accretion rate, and unusual photometric variability suggest that it could be a scaled-down Class II analog of the outbursting FU Ori systems.
Type: article
Authors: Huang, Jane; Andrews, Sean M.; Öberg, Karin I.; Ansdell, Megan; Benisty, Myriam; Carpenter, John M.; Isella, Andrea; Pérez, Laura M.; Ricci, Luca; Williams, Jonathan P.; Wilner, David J.; Zhu, Zhaohuan
Abstract: While protoplanetary disks often appear to be compact and well organized in millimeter continuum emission, CO spectral line observations are increasingly revealing complex behavior at large distances from the host star. We present deep Atacama Large Millimeter/submillimeter Array maps of the J = 2-1 transition of 12CO, 13CO, and C18O, as well as the J = 3-2 transition of DCO+, toward the T Tauri star RU Lup at a resolution of ∼0.3″ (∼50 au). The CO isotopologue emission traces four major components of the RU Lup system: a compact Keplerian disk with a radius of ∼120 au, a non-Keplerian "envelope-like" structure surrounding the disk and extending to ∼260 au from the star, at least five blueshifted spiral arms stretching up to 1000 au, and clumps outside the spiral arms located up to 1500 au in projection from RU Lup. We comment on potential explanations for RU Lup's peculiar gas morphology, including gravitational instability, accretion of material onto the disk, or perturbation by another star. RU Lup's extended non-Keplerian CO emission, elevated stellar accretion rate, and unusual photometric variability suggest that it could be a scaled-down Class II analog of the outbursting FU Ori systems.
A triple-star system with a misaligned and warped circumstellar disk shaped by disk tearingKraus, StefanKreplin, AlexanderYoung, Alison K.Bate, Matthew R.Monnier, John D.Harries, Tim J.Avenhaus, HenningKluska, JacquesLaws, Anna S. E.Rich, Evan A.Willson, MatthewAarnio, Alicia N.Adams, Fred C.Andrews, Sean M.Anugu, NarsireddyBae, Jaehanten Brummelaar, TheoCalvet, NuriaCuré, MichelDavies, Claire L.Ennis, JacobEspaillat, CatherineGardner, TylerHartmann, LeeHinkley, SashaLabdon, AaronLanthermann, CyprienLeBouquin, Jean-BaptisteSchaefer, Gail H.Setterholm, Benjamin R.Wilner, DavidZhu, ZhaohuanDOI: info:10.1126/science.aba4633v. 3691233–1238
Kraus, Stefan, Kreplin, Alexander, Young, Alison K., Bate, Matthew R., Monnier, John D., Harries, Tim J., Avenhaus, Henning, Kluska, Jacques, Laws, Anna S. E., Rich, Evan A., Willson, Matthew, Aarnio, Alicia N., Adams, Fred C., Andrews, Sean M., Anugu, Narsireddy, Bae, Jaehan, ten Brummelaar, Theo, Calvet, Nuria, Curé, Michel, Davies, Claire L., Ennis, Jacob, Espaillat, Catherine, Gardner, Tyler, Hartmann, Lee, Hinkley, Sasha et al. 2020. "A triple-star system with a misaligned and warped circumstellar disk shaped by disk tearing." Science 369:1233– 1238. https://doi.org/10.1126/science.aba4633
ID: 158028
Type: article
Authors: Kraus, Stefan; Kreplin, Alexander; Young, Alison K.; Bate, Matthew R.; Monnier, John D.; Harries, Tim J.; Avenhaus, Henning; Kluska, Jacques; Laws, Anna S. E.; Rich, Evan A.; Willson, Matthew; Aarnio, Alicia N.; Adams, Fred C.; Andrews, Sean M.; Anugu, Narsireddy; Bae, Jaehan; ten Brummelaar, Theo; Calvet, Nuria; Curé, Michel; Davies, Claire L.; Ennis, Jacob; Espaillat, Catherine; Gardner, Tyler; Hartmann, Lee; Hinkley, Sasha; Labdon, Aaron; Lanthermann, Cyprien; LeBouquin, Jean-Baptiste; Schaefer, Gail H.; Setterholm, Benjamin R.; Wilner, David; Zhu, Zhaohuan
Abstract: Young stars are surrounded by a circumstellar disk of gas and dust, within which planet formation can occur. Gravitational forces in multiple star systems can disrupt the disk. Theoretical models predict that if the disk is misaligned with the orbital plane of the stars, the disk should warp and break into precessing rings, a phenomenon known as disk tearing. We present observations of the triple-star system GW Orionis, finding evidence for disk tearing. Our images show an eccentric ring that is misaligned with the orbital planes and the outer disk. The ring casts shadows on a strongly warped intermediate region of the disk. If planets can form within the warped disk, disk tearing could provide a mechanism for forming wide-separation planets on oblique orbits.
Type: article
Authors: Kraus, Stefan; Kreplin, Alexander; Young, Alison K.; Bate, Matthew R.; Monnier, John D.; Harries, Tim J.; Avenhaus, Henning; Kluska, Jacques; Laws, Anna S. E.; Rich, Evan A.; Willson, Matthew; Aarnio, Alicia N.; Adams, Fred C.; Andrews, Sean M.; Anugu, Narsireddy; Bae, Jaehan; ten Brummelaar, Theo; Calvet, Nuria; Curé, Michel; Davies, Claire L.; Ennis, Jacob; Espaillat, Catherine; Gardner, Tyler; Hartmann, Lee; Hinkley, Sasha; Labdon, Aaron; Lanthermann, Cyprien; LeBouquin, Jean-Baptiste; Schaefer, Gail H.; Setterholm, Benjamin R.; Wilner, David; Zhu, Zhaohuan
Abstract: Young stars are surrounded by a circumstellar disk of gas and dust, within which planet formation can occur. Gravitational forces in multiple star systems can disrupt the disk. Theoretical models predict that if the disk is misaligned with the orbital plane of the stars, the disk should warp and break into precessing rings, a phenomenon known as disk tearing. We present observations of the triple-star system GW Orionis, finding evidence for disk tearing. Our images show an eccentric ring that is misaligned with the orbital planes and the outer disk. The ring casts shadows on a strongly warped intermediate region of the disk. If planets can form within the warped disk, disk tearing could provide a mechanism for forming wide-separation planets on oblique orbits.
Irregular Dust Features around Intermediate-mass Young Stars with GPI: Signs of Youth or Misaligned Disks?Laws, Anna S. E.Harries, Tim J.Setterholm, Benjamin R.Monnier, John D.Rich, Evan A.Aarnio, Alicia N.Adams, Fred C.Andrews, SeanBae, JaehanCalvet, NuriaEspaillat, CatherineHartmann, LeeHinkley, SashaIsella, AndreaKraus, StefanWilner, DavidZhu, ZhaohuanDOI: info:10.3847/1538-4357/ab59e2v. 8887
Laws, Anna S. E., Harries, Tim J., Setterholm, Benjamin R., Monnier, John D., Rich, Evan A., Aarnio, Alicia N., Adams, Fred C., Andrews, Sean, Bae, Jaehan, Calvet, Nuria, Espaillat, Catherine, Hartmann, Lee, Hinkley, Sasha, Isella, Andrea, Kraus, Stefan, Wilner, David, and Zhu, Zhaohuan. 2020. "Irregular Dust Features around Intermediate-mass Young Stars with GPI: Signs of Youth or Misaligned Disks?." The Astrophysical Journal 888:7. https://doi.org/10.3847/1538-4357/ab59e2
ID: 155683
Type: article
Authors: Laws, Anna S. E.; Harries, Tim J.; Setterholm, Benjamin R.; Monnier, John D.; Rich, Evan A.; Aarnio, Alicia N.; Adams, Fred C.; Andrews, Sean; Bae, Jaehan; Calvet, Nuria; Espaillat, Catherine; Hartmann, Lee; Hinkley, Sasha; Isella, Andrea; Kraus, Stefan; Wilner, David; Zhu, Zhaohuan
Abstract: We are undertaking a large survey of over 30 disks using the Gemini Planet Imager (GPI) to see whether the observed dust structures match spectral energy distribution predictions and have any correlation with stellar properties. GPI can observe near-infrared light scattered from dust in circumstellar environments using high-resolution Polarimetric Differential Imaging with coronagraphy and adaptive optics. The data have been taken in the J and H bands over two years, with inner working angles of 0.″08 and 0.″11, respectively. Ahead of the release of the complete survey results, here we present five objects with extended and irregular dust structures within 2″ of the central star. These objects are FU Ori, MWC 789, HD 45677, Hen 3-365, and HD 139614. The observed structures are consistent with each object being a pre-main-sequence star with protoplanetary dust. The five objects' circumstellar environments could result from extreme youth and complex initial conditions, from asymmetric scattering patterns due to shadows cast by misaligned disks, or in some cases from interactions with companions. We see complex U ϕ structures in most objects that could indicate multiple scattering or result from the illumination of companions. Specific key findings include the first high-contrast observation of MWC 789 revealing a newly discovered companion candidate and arc, and two faint companion candidates around Hen 3-365. These two objects should be observed further to confirm whether the companion candidates are comoving. Further observations and modeling are required to determine the causes of the structures.
Type: article
Authors: Laws, Anna S. E.; Harries, Tim J.; Setterholm, Benjamin R.; Monnier, John D.; Rich, Evan A.; Aarnio, Alicia N.; Adams, Fred C.; Andrews, Sean; Bae, Jaehan; Calvet, Nuria; Espaillat, Catherine; Hartmann, Lee; Hinkley, Sasha; Isella, Andrea; Kraus, Stefan; Wilner, David; Zhu, Zhaohuan
Abstract: We are undertaking a large survey of over 30 disks using the Gemini Planet Imager (GPI) to see whether the observed dust structures match spectral energy distribution predictions and have any correlation with stellar properties. GPI can observe near-infrared light scattered from dust in circumstellar environments using high-resolution Polarimetric Differential Imaging with coronagraphy and adaptive optics. The data have been taken in the J and H bands over two years, with inner working angles of 0.″08 and 0.″11, respectively. Ahead of the release of the complete survey results, here we present five objects with extended and irregular dust structures within 2″ of the central star. These objects are FU Ori, MWC 789, HD 45677, Hen 3-365, and HD 139614. The observed structures are consistent with each object being a pre-main-sequence star with protoplanetary dust. The five objects' circumstellar environments could result from extreme youth and complex initial conditions, from asymmetric scattering patterns due to shadows cast by misaligned disks, or in some cases from interactions with companions. We see complex U ϕ structures in most objects that could indicate multiple scattering or result from the illumination of companions. Specific key findings include the first high-contrast observation of MWC 789 revealing a newly discovered companion candidate and arc, and two faint companion candidates around Hen 3-365. These two objects should be observed further to confirm whether the companion candidates are comoving. Further observations and modeling are required to determine the causes of the structures.
Dual-wavelength ALMA Observations of Dust Rings in Protoplanetary DisksLong, FengPinilla, PaolaHerczeg, Gregory J.Andrews, Sean M.Harsono, DanielJohnstone, DougRagusa, EnricoPascucci, IlariaWilner, David J.Hendler, NathanJennings, JeffLiu, YaoLodato, GiuseppeMenard, Francoisvan de Plas, GerritDipierro, GiovanniDOI: info:10.3847/1538-4357/ab9a54v. 89836
Long, Feng, Pinilla, Paola, Herczeg, Gregory J., Andrews, Sean M., Harsono, Daniel, Johnstone, Doug, Ragusa, Enrico, Pascucci, Ilaria, Wilner, David J., Hendler, Nathan, Jennings, Jeff, Liu, Yao, Lodato, Giuseppe, Menard, Francois, van de Plas, Gerrit, and Dipierro, Giovanni. 2020. "Dual-wavelength ALMA Observations of Dust Rings in Protoplanetary Disks." The Astrophysical Journal 898:36. https://doi.org/10.3847/1538-4357/ab9a54
ID: 157657
Type: article
Authors: Long, Feng; Pinilla, Paola; Herczeg, Gregory J.; Andrews, Sean M.; Harsono, Daniel; Johnstone, Doug; Ragusa, Enrico; Pascucci, Ilaria; Wilner, David J.; Hendler, Nathan; Jennings, Jeff; Liu, Yao; Lodato, Giuseppe; Menard, Francois; van de Plas, Gerrit; Dipierro, Giovanni
Abstract: We present new Atacama Large Millimeter/submillimeter Array observations for three protoplanetary disks in Taurus at 2.9 mm and comparisons with previous 1.3 mm data both at an angular resolution of ∼0"1 (15 au for the distance of Taurus). In the single-ring disk DS Tau, double-ring disk GO Tau, and multiring disk DL Tau, the same rings are detected at both wavelengths, with radial locations spanning from 50 to 120 au. To quantify the dust emission morphology, the observed visibilities are modeled with a parametric prescription for the radial intensity profile. The disk outer radii, taken as 95% of the total flux encircled in the model intensity profiles, are consistent at both wavelengths for the three disks. Dust evolution models show that dust trapping in local pressure maxima in the outer disk could explain the observed patterns. Dust rings are mostly unresolved. The marginally resolved ring in DS Tau shows a tentatively narrower ring at the longer wavelength, an observational feature expected from efficient dust trapping. The spectral index (αmm) increases outward and exhibits local minima that correspond to the peaks of dust rings, indicative of the changes in grain properties across the disks. The low optical depths (τ ∼ 0.1-0.2 at 2.9 mm and 0.2-0.4 at 1.3 mm) in the dust rings suggest that grains in the rings may have grown to millimeter sizes. The ubiquitous dust rings in protoplanetary disks modify the overall dynamics and evolution of dust grains, likely paving the way toward the new generation of planet formation.
Type: article
Authors: Long, Feng; Pinilla, Paola; Herczeg, Gregory J.; Andrews, Sean M.; Harsono, Daniel; Johnstone, Doug; Ragusa, Enrico; Pascucci, Ilaria; Wilner, David J.; Hendler, Nathan; Jennings, Jeff; Liu, Yao; Lodato, Giuseppe; Menard, Francois; van de Plas, Gerrit; Dipierro, Giovanni
Abstract: We present new Atacama Large Millimeter/submillimeter Array observations for three protoplanetary disks in Taurus at 2.9 mm and comparisons with previous 1.3 mm data both at an angular resolution of ∼0"1 (15 au for the distance of Taurus). In the single-ring disk DS Tau, double-ring disk GO Tau, and multiring disk DL Tau, the same rings are detected at both wavelengths, with radial locations spanning from 50 to 120 au. To quantify the dust emission morphology, the observed visibilities are modeled with a parametric prescription for the radial intensity profile. The disk outer radii, taken as 95% of the total flux encircled in the model intensity profiles, are consistent at both wavelengths for the three disks. Dust evolution models show that dust trapping in local pressure maxima in the outer disk could explain the observed patterns. Dust rings are mostly unresolved. The marginally resolved ring in DS Tau shows a tentatively narrower ring at the longer wavelength, an observational feature expected from efficient dust trapping. The spectral index (αmm) increases outward and exhibits local minima that correspond to the peaks of dust rings, indicative of the changes in grain properties across the disks. The low optical depths (τ ∼ 0.1-0.2 at 2.9 mm and 0.2-0.4 at 1.3 mm) in the dust rings suggest that grains in the rings may have grown to millimeter sizes. The ubiquitous dust rings in protoplanetary disks modify the overall dynamics and evolution of dust grains, likely paving the way toward the new generation of planet formation.
An Unbiased ALMA Spectral Survey of the LkCa 15 and MWC 480 Protoplanetary DisksLoomis, Ryan A.Öberg, Karin I.Andrews, Sean M.Bergin, EdwinBergner, JenniferBlake, Geoffrey A.Cleeves, L. IlsedoreCzekala, IanHuang, JaneLe Gal, RomaneMénard, FrancoisPegues, JamilaQi, ChunhuaWalsh, CatherineWilliams, Jonathan P.Wilner, David J.DOI: info:10.3847/1538-4357/ab7cc8v. 893101
Loomis, Ryan A., Öberg, Karin I., Andrews, Sean M., Bergin, Edwin, Bergner, Jennifer, Blake, Geoffrey A., Cleeves, L. Ilsedore, Czekala, Ian, Huang, Jane, Le Gal, Romane, Ménard, Francois, Pegues, Jamila, Qi, Chunhua, Walsh, Catherine, Williams, Jonathan P., and Wilner, David J. 2020. "An Unbiased ALMA Spectral Survey of the LkCa 15 and MWC 480 Protoplanetary Disks." The Astrophysical Journal 893:101. https://doi.org/10.3847/1538-4357/ab7cc8
ID: 157298
Type: article
Authors: Loomis, Ryan A.; Öberg, Karin I.; Andrews, Sean M.; Bergin, Edwin; Bergner, Jennifer; Blake, Geoffrey A.; Cleeves, L. Ilsedore; Czekala, Ian; Huang, Jane; Le Gal, Romane; Ménard, Francois; Pegues, Jamila; Qi, Chunhua; Walsh, Catherine; Williams, Jonathan P.; Wilner, David J.
Abstract: The volatile contents of protoplanetary disks both set the potential for planetary chemistry and provide valuable probes of defining disk system characteristics such as stellar mass, gas mass, ionization, and temperature structure. Current disk molecular inventories are fragmented, however, giving an incomplete picture: unbiased spectral line surveys are needed to assess the volatile content. We present here an overview of such a survey of the protoplanetary disks around the Herbig Ae star MWC 480 and the T Tauri star LkCa 15 in ALMA Band 7, spanning ∼36 GHz from 275 to 317 GHz and representing an order of magnitude increase in sensitivity over previous single-dish surveys. We detect 14 molecular species (including isotopologues), with five species (C34S, 13CS, H2CS, DNC, and C2D) detected for the first time in protoplanetary disks. Significant differences are observed in the molecular inventories of MWC 480 and LkCa 15, and we discuss how these results may be interpreted in light of the different physical conditions of these two disk systems.
Type: article
Authors: Loomis, Ryan A.; Öberg, Karin I.; Andrews, Sean M.; Bergin, Edwin; Bergner, Jennifer; Blake, Geoffrey A.; Cleeves, L. Ilsedore; Czekala, Ian; Huang, Jane; Le Gal, Romane; Ménard, Francois; Pegues, Jamila; Qi, Chunhua; Walsh, Catherine; Williams, Jonathan P.; Wilner, David J.
Abstract: The volatile contents of protoplanetary disks both set the potential for planetary chemistry and provide valuable probes of defining disk system characteristics such as stellar mass, gas mass, ionization, and temperature structure. Current disk molecular inventories are fragmented, however, giving an incomplete picture: unbiased spectral line surveys are needed to assess the volatile content. We present here an overview of such a survey of the protoplanetary disks around the Herbig Ae star MWC 480 and the T Tauri star LkCa 15 in ALMA Band 7, spanning ∼36 GHz from 275 to 317 GHz and representing an order of magnitude increase in sensitivity over previous single-dish surveys. We detect 14 molecular species (including isotopologues), with five species (C34S, 13CS, H2CS, DNC, and C2D) detected for the first time in protoplanetary disks. Significant differences are observed in the molecular inventories of MWC 480 and LkCa 15, and we discuss how these results may be interpreted in light of the different physical conditions of these two disk systems.
An ALMA Survey of H2CO in Protoplanetary DisksPegues, JamilaÖberg, Karin I.Bergner, Jennifer B.Loomis, Ryan A.Qi, ChunhuaLe Gal, RomaneCleeves, L. IlsedoreGuzmán, Viviana V.Huang, JaneJørgensen, Jes K.Andrews, Sean M.Blake, Geoffrey A.Carpenter, John M.Schwarz, Kamber R.Williams, Jonathan P.Wilner, David J.DOI: info:10.3847/1538-4357/ab64d9v. 890142
Pegues, Jamila, Öberg, Karin I., Bergner, Jennifer B., Loomis, Ryan A., Qi, Chunhua, Le Gal, Romane, Cleeves, L. Ilsedore, Guzmán, Viviana V., Huang, Jane, Jørgensen, Jes K., Andrews, Sean M., Blake, Geoffrey A., Carpenter, John M., Schwarz, Kamber R., Williams, Jonathan P., and Wilner, David J. 2020. "An ALMA Survey of H2CO in Protoplanetary Disks." The Astrophysical Journal 890:142. https://doi.org/10.3847/1538-4357/ab64d9
ID: 155824
Type: article
Authors: Pegues, Jamila; Öberg, Karin I.; Bergner, Jennifer B.; Loomis, Ryan A.; Qi, Chunhua; Le Gal, Romane; Cleeves, L. Ilsedore; Guzmán, Viviana V.; Huang, Jane; Jørgensen, Jes K.; Andrews, Sean M.; Blake, Geoffrey A.; Carpenter, John M.; Schwarz, Kamber R.; Williams, Jonathan P.; Wilner, David J.
Abstract: H2CO is one of the most abundant organic molecules in protoplanetary disks and can serve as a precursor to more complex organic chemistry. We present an Atacama Large Millimeter/submillimeter Array survey of H2CO toward 15 disks covering a range of stellar spectral types, stellar ages, and dust continuum morphologies. H2CO is detected toward 13 disks and tentatively detected toward a fourteenth. We find both centrally peaked and centrally depressed emission morphologies, and half of the disks show ring-like structures at or beyond expected CO snowline locations. Together these morphologies suggest that H2CO in disks is commonly produced through both gas-phase and CO-ice-regulated grain-surface chemistry. We extract disk-averaged and azimuthally-averaged H2CO excitation temperatures and column densities for four disks with multiple H2CO line detections. The temperatures are between 20─50 K, with the exception of colder temperatures in the DM Tau disk. These temperatures suggest that H2CO emission in disks generally emerges from the warm molecular layer, with some contributions from the colder midplane. Applying the same H2CO excitation temperatures to all disks in the survey, we find that H2CO column densities span almost three orders of magnitude (∼5 × 1011─5 × 1014 cm−2). The column densities appear uncorrelated with disk size and stellar age, but Herbig Ae disks may have less H2CO compared to T Tauri disks, possibly because of less CO freeze-out. More H2CO observations toward Herbig Ae disks are needed to confirm this tentative trend, and to better constrain under which disk conditions H2CO and other oxygen-bearing organics efficiently form during planet formation.
Type: article
Authors: Pegues, Jamila; Öberg, Karin I.; Bergner, Jennifer B.; Loomis, Ryan A.; Qi, Chunhua; Le Gal, Romane; Cleeves, L. Ilsedore; Guzmán, Viviana V.; Huang, Jane; Jørgensen, Jes K.; Andrews, Sean M.; Blake, Geoffrey A.; Carpenter, John M.; Schwarz, Kamber R.; Williams, Jonathan P.; Wilner, David J.
Abstract: H2CO is one of the most abundant organic molecules in protoplanetary disks and can serve as a precursor to more complex organic chemistry. We present an Atacama Large Millimeter/submillimeter Array survey of H2CO toward 15 disks covering a range of stellar spectral types, stellar ages, and dust continuum morphologies. H2CO is detected toward 13 disks and tentatively detected toward a fourteenth. We find both centrally peaked and centrally depressed emission morphologies, and half of the disks show ring-like structures at or beyond expected CO snowline locations. Together these morphologies suggest that H2CO in disks is commonly produced through both gas-phase and CO-ice-regulated grain-surface chemistry. We extract disk-averaged and azimuthally-averaged H2CO excitation temperatures and column densities for four disks with multiple H2CO line detections. The temperatures are between 20─50 K, with the exception of colder temperatures in the DM Tau disk. These temperatures suggest that H2CO emission in disks generally emerges from the warm molecular layer, with some contributions from the colder midplane. Applying the same H2CO excitation temperatures to all disks in the survey, we find that H2CO column densities span almost three orders of magnitude (∼5 × 1011─5 × 1014 cm−2). The column densities appear uncorrelated with disk size and stellar age, but Herbig Ae disks may have less H2CO compared to T Tauri disks, possibly because of less CO freeze-out. More H2CO observations toward Herbig Ae disks are needed to confirm this tentative trend, and to better constrain under which disk conditions H2CO and other oxygen-bearing organics efficiently form during planet formation.
Nine Localized Deviations from Keplerian Rotation in the DSHARP Circumstellar Disks: Kinematic Evidence for Protoplanets Carving the GapsPinte, C.Price, D. J.Ménard, F.Duchêne, G.Christiaens, V.Andrews, Sean M.Huang, JiashengHill, T.van der Plas, G.Perez, L. M.Isella, A.Boehler, Y.Dent, W. R. F.Mentiplay, D.Loomis, R. A.DOI: info:10.3847/2041-8213/ab6ddav. 890L9
Pinte, C., Price, D. J., Ménard, F., Duchêne, G., Christiaens, V., Andrews, Sean M., Huang, Jiasheng, Hill, T., van der Plas, G., Perez, L. M., Isella, A., Boehler, Y., Dent, W. R. F., Mentiplay, D., and Loomis, R. A. 2020. "Nine Localized Deviations from Keplerian Rotation in the DSHARP Circumstellar Disks: Kinematic Evidence for Protoplanets Carving the Gaps." The Astrophysical Journal 890:L9. https://doi.org/10.3847/2041-8213/ab6dda
ID: 156216
Type: article
Authors: Pinte, C.; Price, D. J.; Ménard, F.; Duchêne, G.; Christiaens, V.; Andrews, Sean M.; Huang, Jiasheng; Hill, T.; van der Plas, G.; Perez, L. M.; Isella, A.; Boehler, Y.; Dent, W. R. F.; Mentiplay, D.; Loomis, R. A.
Abstract: We present evidence for localized deviations from Keplerian rotation, i.e., velocity "kinks," in 8 of the 18 circumstellar disks observed by the DSHARP program: DoAr 25, Elias 2─27, GW Lup, HD 143006, HD 163296, IM Lup, Sz 129, and WaOph 6. Most of the kinks are detected over a small range in both radial extent and velocity, suggesting a planetary origin, but for some of them foreground contamination prevents us from measuring their spatial and velocity extent. Because of the DSHARP limited spectral resolution and signal to noise in the 12CO J = 2−1 line, as well as cloud contamination, the kinks are usually detected in only one spectral channel, and will require confirmation. The strongest circumstantial evidence for protoplanets in the absence of higher spectral resolution data and additional tracers is that, upon deprojection, we find that all of the candidate planets lie within a gap and/or at the end of a spiral detected in dust continuum emission. This suggests that a significant fraction of the dust gaps and spirals observed by Atacama Large Millimeter/submillimeter Array in disks are caused by embedded protoplanets.
Type: article
Authors: Pinte, C.; Price, D. J.; Ménard, F.; Duchêne, G.; Christiaens, V.; Andrews, Sean M.; Huang, Jiasheng; Hill, T.; van der Plas, G.; Perez, L. M.; Isella, A.; Boehler, Y.; Dent, W. R. F.; Mentiplay, D.; Loomis, R. A.
Abstract: We present evidence for localized deviations from Keplerian rotation, i.e., velocity "kinks," in 8 of the 18 circumstellar disks observed by the DSHARP program: DoAr 25, Elias 2─27, GW Lup, HD 143006, HD 163296, IM Lup, Sz 129, and WaOph 6. Most of the kinks are detected over a small range in both radial extent and velocity, suggesting a planetary origin, but for some of them foreground contamination prevents us from measuring their spatial and velocity extent. Because of the DSHARP limited spectral resolution and signal to noise in the 12CO J = 2−1 line, as well as cloud contamination, the kinks are usually detected in only one spectral channel, and will require confirmation. The strongest circumstantial evidence for protoplanets in the absence of higher spectral resolution data and additional tracers is that, upon deprojection, we find that all of the candidate planets lie within a gap and/or at the end of a spiral detected in dust continuum emission. This suggests that a significant fraction of the dust gaps and spirals observed by Atacama Large Millimeter/submillimeter Array in disks are caused by embedded protoplanets.
Erratum: 'Far-infrared to Millimeter Data of Protoplanetary Disks: Dust Growth in the Taurus, Ophiuchus, and Chamaeleon I Star-forming Regions' (2017, ApJ, 849, 63)Ribas, ÁlvaroEspaillat, Catherine C.Macías, EnriqueBouy, HervéAndrews, SeanCalvet, NuriaNaylor, David A.Riviere-Marichalar, Pablovan der Wiel, Matthijs H. D.Wilner, DavidDOI: info:10.3847/1538-4357/abb66ev. 90188
Ribas, Álvaro, Espaillat, Catherine C., Macías, Enrique, Bouy, Hervé, Andrews, Sean, Calvet, Nuria, Naylor, David A., Riviere-Marichalar, Pablo, van der Wiel, Matthijs H. D., and Wilner, David. 2020. "Erratum: "Far-infrared to Millimeter Data of Protoplanetary Disks: Dust Growth in the Taurus, Ophiuchus, and Chamaeleon I Star-forming Regions" (2017, ApJ, 849, 63)." The Astrophysical Journal 901:88. https://doi.org/10.3847/1538-4357/abb66e
ID: 157613
Type: article
Authors: Ribas, Álvaro; Espaillat, Catherine C.; Macías, Enrique; Bouy, Hervé; Andrews, Sean; Calvet, Nuria; Naylor, David A.; Riviere-Marichalar, Pablo; van der Wiel, Matthijs H. D.; Wilner, David
Type: article
Authors: Ribas, Álvaro; Espaillat, Catherine C.; Macías, Enrique; Bouy, Hervé; Andrews, Sean; Calvet, Nuria; Naylor, David A.; Riviere-Marichalar, Pablo; van der Wiel, Matthijs H. D.; Wilner, David
Protoplanetary disk masses in NGC 2024: Evidence for two populationsvan Terwisga, S. E.van Dishoeck, E. F.Mann, R. K.Di Francesco, J.van der Marel, N.Meyer, M.Andrews, Sean M.Carpenter, J.Eisner, J. A.Manara, C. F.Williams, J. P.DOI: info:10.1051/0004-6361/201937403v. 640A27
van Terwisga, S. E., van Dishoeck, E. F., Mann, R. K., Di Francesco, J., van der Marel, N., Meyer, M., Andrews, Sean M., Carpenter, J., Eisner, J. A., Manara, C. F., and Williams, J. P. 2020. "Protoplanetary disk masses in NGC 2024: Evidence for two populations." Astronomy and Astrophysics 640:A27. https://doi.org/10.1051/0004-6361/201937403
ID: 157661
Type: article
Authors: van Terwisga, S. E.; van Dishoeck, E. F.; Mann, R. K.; Di Francesco, J.; van der Marel, N.; Meyer, M.; Andrews, Sean M.; Carpenter, J.; Eisner, J. A.; Manara, C. F.; Williams, J. P.
Abstract: Context. Protoplanetary disks in dense, massive star-forming regions are strongly affected by their environment. How this environmental impact changes over time is an important constraint on disk evolution and external photoevaporation models.
Aims: We characterize the dust emission from 179 disks in the core of the young (0.5 Myr) NGC 2024 cluster. By studying how the disk mass varies within the cluster, and comparing these disks to those in other regions, we aim to determine how external photoevaporation influences disk properties over time.
Methods: Using the Atacama Large Millimeter/submillimeter Array, a 2.9'× 2.9' mosaic centered on NGC 2024 FIR 3 was observed at 225 GHz with a resolution of 0.25″, or ~100 AU. The imaged region contains 179 disks identified at IR wavelengths, seven new disk candidates, and several protostars.
Results: The overall detection rate of disks is 32 ± 4%. Few of the disks are resolved, with the exception of a giant (R = 300 AU) transition disk. Serendipitously, we observe a millimeter flare from an X-ray bright young stellar object (YSO), and resolve continuum emission from a Class 0 YSO in the FIR 3 core. Two distinct disk populations are present: a more massive one in the east, along the dense molecular ridge hosting the FIR 1-5 YSOs, with a detection rate of 45 ± 7%. In the western population, towards IRS 1, only 15 ± 4% of disks are detected.
Conclusions: NGC 2024 hosts two distinct disk populations. Disks along the dense molecular ridge are young (0.2-0.5 Myr) and partly shielded from the far ultraviolet radiation of IRS 2b; their masses are similar to isolated 1-3 Myr old SFRs. The western population is older and at lower extinctions, and may be affected by external photoevaporation from both IRS 1 and IRS 2b. However, it is possible these disks had lower masses to begin with.
Tables 1, 2, and B.1 and FITS figure are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/640/A27
Type: article
Authors: van Terwisga, S. E.; van Dishoeck, E. F.; Mann, R. K.; Di Francesco, J.; van der Marel, N.; Meyer, M.; Andrews, Sean M.; Carpenter, J.; Eisner, J. A.; Manara, C. F.; Williams, J. P.
Abstract: Context. Protoplanetary disks in dense, massive star-forming regions are strongly affected by their environment. How this environmental impact changes over time is an important constraint on disk evolution and external photoevaporation models.
Aims: We characterize the dust emission from 179 disks in the core of the young (0.5 Myr) NGC 2024 cluster. By studying how the disk mass varies within the cluster, and comparing these disks to those in other regions, we aim to determine how external photoevaporation influences disk properties over time.
Methods: Using the Atacama Large Millimeter/submillimeter Array, a 2.9'× 2.9' mosaic centered on NGC 2024 FIR 3 was observed at 225 GHz with a resolution of 0.25″, or ~100 AU. The imaged region contains 179 disks identified at IR wavelengths, seven new disk candidates, and several protostars.
Results: The overall detection rate of disks is 32 ± 4%. Few of the disks are resolved, with the exception of a giant (R = 300 AU) transition disk. Serendipitously, we observe a millimeter flare from an X-ray bright young stellar object (YSO), and resolve continuum emission from a Class 0 YSO in the FIR 3 core. Two distinct disk populations are present: a more massive one in the east, along the dense molecular ridge hosting the FIR 1-5 YSOs, with a detection rate of 45 ± 7%. In the western population, towards IRS 1, only 15 ± 4% of disks are detected.
Conclusions: NGC 2024 hosts two distinct disk populations. Disks along the dense molecular ridge are young (0.2-0.5 Myr) and partly shielded from the far ultraviolet radiation of IRS 2b; their masses are similar to isolated 1-3 Myr old SFRs. The western population is older and at lower extinctions, and may be affected by external photoevaporation from both IRS 1 and IRS 2b. However, it is possible these disks had lower masses to begin with.
Tables 1, 2, and B.1 and FITS figure are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/640/A27
ALMA 0.88 mm Survey of Disks around Planetary-mass CompanionsWu, Ya-LinBowler, Brendan P.Sheehan, Patrick D.Andrews, Sean M.Herczeg, Gregory J.Kraus, Adam L.Ricci, LucaWilner, David J.Zhu, ZhaohuanDOI: info:10.3847/1538-3881/ab818cv. 159229
Wu, Ya-Lin, Bowler, Brendan P., Sheehan, Patrick D., Andrews, Sean M., Herczeg, Gregory J., Kraus, Adam L., Ricci, Luca, Wilner, David J., and Zhu, Zhaohuan. 2020. "ALMA 0.88 mm Survey of Disks around Planetary-mass Companions." The Astronomical Journal 159:229. https://doi.org/10.3847/1538-3881/ab818c
ID: 156975
Type: article
Authors: Wu, Ya-Lin; Bowler, Brendan P.; Sheehan, Patrick D.; Andrews, Sean M.; Herczeg, Gregory J.; Kraus, Adam L.; Ricci, Luca; Wilner, David J.; Zhu, Zhaohuan
Abstract: Characterizing the physical properties and compositions of circumplanetary disks can provide important insights into the formation of giant planets and satellites. We report Atacama Large Millimeter/submillimeter Array 0.88 mm (Band 7) continuum observations of six planetary-mass (10-20 MJup) companions: CT Cha b, 1RXS 1609 b, ROXs 12 b, ROXs 42B b, DH Tau b, and FU Tau b. No continuum sources are detected at the locations of the companions down to 3σ limits of 120-210 μJy. Given these nondetections, it is not clear whether disks around planetary-mass companions indeed follow the disk- flux-host-mass trend in the stellar regime. The faint radio brightness of these companion disks may result from a combination of fast radial drift and a lack of dust traps. Alternatively, as disks in binary systems are known to have significantly lower millimeter fluxes due to tidal interactions, these companion disks may instead follow the relationship of moderate-separation binary stars. This scenario can be tested with sensitive continuum imaging at rms levels of ≲10 μJy.
Type: article
Authors: Wu, Ya-Lin; Bowler, Brendan P.; Sheehan, Patrick D.; Andrews, Sean M.; Herczeg, Gregory J.; Kraus, Adam L.; Ricci, Luca; Wilner, David J.; Zhu, Zhaohuan
Abstract: Characterizing the physical properties and compositions of circumplanetary disks can provide important insights into the formation of giant planets and satellites. We report Atacama Large Millimeter/submillimeter Array 0.88 mm (Band 7) continuum observations of six planetary-mass (10-20 MJup) companions: CT Cha b, 1RXS 1609 b, ROXs 12 b, ROXs 42B b, DH Tau b, and FU Tau b. No continuum sources are detected at the locations of the companions down to 3σ limits of 120-210 μJy. Given these nondetections, it is not clear whether disks around planetary-mass companions indeed follow the disk- flux-host-mass trend in the stellar regime. The faint radio brightness of these companion disks may result from a combination of fast radial drift and a lack of dust traps. Alternatively, as disks in binary systems are known to have significantly lower millimeter fluxes due to tidal interactions, these companion disks may instead follow the relationship of moderate-separation binary stars. This scenario can be tested with sensitive continuum imaging at rms levels of ≲10 μJy.
The Degree of Alignment between Circumbinary Disks and Their Binary HostsCzekala, IanChiang, EugeneAndrews, Sean M.Jensen, Eric L. N.Torres, GuillermoWilner, David J.Stassun, Keivan G.Macintosh, BruceDOI: info:10.3847/1538-4357/ab287bv. 88322
Czekala, Ian, Chiang, Eugene, Andrews, Sean M., Jensen, Eric L. N., Torres, Guillermo, Wilner, David J., Stassun, Keivan G., and Macintosh, Bruce. 2019. "The Degree of Alignment between Circumbinary Disks and Their Binary Hosts." The Astrophysical Journal 883:22. https://doi.org/10.3847/1538-4357/ab287b
ID: 154408
Type: article
Authors: Czekala, Ian; Chiang, Eugene; Andrews, Sean M.; Jensen, Eric L. N.; Torres, Guillermo; Wilner, David J.; Stassun, Keivan G.; Macintosh, Bruce
Abstract: All four circumbinary (CB) protoplanetary disks orbiting short-period (P disk that match, to within a few degrees, the sky-plane inclinations i ⋆ of their stellar hosts. Although for these systems the true mutual inclinations θ between disk and binary cannot be directly measured because relative nodal angles are unknown, the near coincidence of i disk and i ⋆ suggests that θ is small for these most compact of systems. We confirm this hypothesis using a hierarchical Bayesian analysis, showing that 68% of CB disks around short-period SB2s have θ suggests that θ is small for these most compact of systems. We confirm this hypothesis using a hierarchical Bayesian analysis, showing that 68% of CB disks around short-period SB2s have θ 5 days (where the nodal degeneracy can be broken via, e.g., binary astrometry), CB disks exhibit a wide range of mutual inclinations, from coplanar to polar. Many of these long-period binaries are eccentric, as their component stars are too far separated to be tidally circularized. We discuss how theories of binary formation and disk-binary gravitational interactions can accommodate all these observations.
Type: article
Authors: Czekala, Ian; Chiang, Eugene; Andrews, Sean M.; Jensen, Eric L. N.; Torres, Guillermo; Wilner, David J.; Stassun, Keivan G.; Macintosh, Bruce
Abstract: All four circumbinary (CB) protoplanetary disks orbiting short-period (P disk that match, to within a few degrees, the sky-plane inclinations i ⋆ of their stellar hosts. Although for these systems the true mutual inclinations θ between disk and binary cannot be directly measured because relative nodal angles are unknown, the near coincidence of i disk and i ⋆ suggests that θ is small for these most compact of systems. We confirm this hypothesis using a hierarchical Bayesian analysis, showing that 68% of CB disks around short-period SB2s have θ suggests that θ is small for these most compact of systems. We confirm this hypothesis using a hierarchical Bayesian analysis, showing that 68% of CB disks around short-period SB2s have θ 5 days (where the nodal degeneracy can be broken via, e.g., binary astrometry), CB disks exhibit a wide range of mutual inclinations, from coplanar to polar. Many of these long-period binaries are eccentric, as their component stars are too far separated to be tidally circularized. We discuss how theories of binary formation and disk-binary gravitational interactions can accommodate all these observations.
The Mass of Stirring Bodies in the AU Mic Debris Disk Inferred from Resolved Vertical StructureDaley, CailHughes, A. MeredithCarter, Evan S.Flaherty, KevinLambros, ZacharyPan, MargaretSchlichting, HilkeChiang, EugeneWyatt, MarkWilner, DavidAndrews, SeanCarpenter, JohnDOI: info:10.3847/1538-4357/ab1074v. 87587
Daley, Cail, Hughes, A. Meredith, Carter, Evan S., Flaherty, Kevin, Lambros, Zachary, Pan, Margaret, Schlichting, Hilke, Chiang, Eugene, Wyatt, Mark, Wilner, David, Andrews, Sean, and Carpenter, John. 2019. "The Mass of Stirring Bodies in the AU Mic Debris Disk Inferred from Resolved Vertical Structure." The Astrophysical Journal 875:87. https://doi.org/10.3847/1538-4357/ab1074
ID: 155314
Type: article
Authors: Daley, Cail; Hughes, A. Meredith; Carter, Evan S.; Flaherty, Kevin; Lambros, Zachary; Pan, Margaret; Schlichting, Hilke; Chiang, Eugene; Wyatt, Mark; Wilner, David; Andrews, Sean; Carpenter, John
Abstract: The vertical distribution of dust in debris disks is sensitive to the number and size of large planetesimals dynamically stirring the disk, and is therefore well-suited for constraining the prevalence of otherwise unobservable Uranus and Neptune analogs. Information regarding stirring bodies has previously been inferred from infrared and optical observations of debris disk vertical structure, but theoretical works predict that the small particles traced by short-wavelength observations will be "puffed up" by radiation pressure, yielding only upper limits. The large grains that dominate the disk emission at millimeter wavelengths are much less sensitive to the effects of stellar radiation or stellar winds, and therefore trace the underlying mass distribution more directly. Here we present ALMA 1.3 mm dust continuum observations of the debris disk around the nearby M star AU Mic. The 3 au spatial resolution of the observations, combined with the favorable edge-on geometry of the system, allows us to measure the vertical thickness of the disk. We report a scale height-to-radius aspect ratio of h={0.031}-0.004+0.005 between radii of ∼23 au and ∼41 au. Comparing this aspect ratio to a theoretical model of size- dependent velocity distributions in the collisional cascade, we find that the perturbing bodies embedded in the local disk must be larger than about 400 km, and the largest perturbing body must be smaller than roughly 1.8 M ⊕. These measurements rule out the presence of a gas giant or Neptune analog near the ∼40 au outer edge of the debris ring, but are suggestive of large planetesimals or an Earth-sized planet stirring the dust distribution.
Type: article
Authors: Daley, Cail; Hughes, A. Meredith; Carter, Evan S.; Flaherty, Kevin; Lambros, Zachary; Pan, Margaret; Schlichting, Hilke; Chiang, Eugene; Wyatt, Mark; Wilner, David; Andrews, Sean; Carpenter, John
Abstract: The vertical distribution of dust in debris disks is sensitive to the number and size of large planetesimals dynamically stirring the disk, and is therefore well-suited for constraining the prevalence of otherwise unobservable Uranus and Neptune analogs. Information regarding stirring bodies has previously been inferred from infrared and optical observations of debris disk vertical structure, but theoretical works predict that the small particles traced by short-wavelength observations will be "puffed up" by radiation pressure, yielding only upper limits. The large grains that dominate the disk emission at millimeter wavelengths are much less sensitive to the effects of stellar radiation or stellar winds, and therefore trace the underlying mass distribution more directly. Here we present ALMA 1.3 mm dust continuum observations of the debris disk around the nearby M star AU Mic. The 3 au spatial resolution of the observations, combined with the favorable edge-on geometry of the system, allows us to measure the vertical thickness of the disk. We report a scale height-to-radius aspect ratio of h={0.031}-0.004+0.005 between radii of ∼23 au and ∼41 au. Comparing this aspect ratio to a theoretical model of size- dependent velocity distributions in the collisional cascade, we find that the perturbing bodies embedded in the local disk must be larger than about 400 km, and the largest perturbing body must be smaller than roughly 1.8 M ⊕. These measurements rule out the presence of a gas giant or Neptune analog near the ∼40 au outer edge of the debris ring, but are suggestive of large planetesimals or an Earth-sized planet stirring the dust distribution.