Publication Search Results

Search Results

Showing 1-20 of about 161 results.
Stellar Radial Velocities in the Old Open Cluster M67 (NGC 2682). II. The Spectroscopic Binary PopulationGeller, Aaron M.Mathieu, Robert D.Latham, David W.Pollack, MaxwellTorres, GuillermoLeiner, Emily M.DOI: info:10.3847/1538-3881/abdd23v. 161190
Geller, Aaron M., Mathieu, Robert D., Latham, David W., Pollack, Maxwell, Torres, Guillermo, and Leiner, Emily M. 2021. "Stellar Radial Velocities in the Old Open Cluster M67 (NGC 2682). II. The Spectroscopic Binary Population." The Astronomical Journal 161:190.
ID: 159321
Type: article
Authors: Geller, Aaron M.; Mathieu, Robert D.; Latham, David W.; Pollack, Maxwell; Torres, Guillermo; Leiner, Emily M.
Abstract: We present and analyze 120 spectroscopic binary and triple cluster members of the old (4 Gyr) open cluster M67 (NGC 2682). As a cornerstone of stellar astrophysics, M67 is a key cluster in the WIYN Open Cluster Study (WOCS); radial-velocity (RV) observations of M67 are ongoing and extend back over 45 yr, incorporating data from seven different telescopes, and allowing us to detect binaries with orbital periods ≲104 days. Our sample contains 1296 stars (604 cluster members) with magnitudes of 10 ≤ V ≤ 16.5 (about 1.3-0.7 M), from the giants down to ∼4 mag below the main-sequence turnoff, and extends in radius to 30' (7.4 pc at a distance of 850 pc, or ∼7 core radii). This paper focuses primarily on the main-sequence binaries, but orbital solutions are also presented for red giants, yellow giants, and sub-subgiants. Out to our period detection limit and within our magnitude and spatial domain, we find a global main-sequence incompleteness-corrected binary fraction of 34% ± 3%, which rises to 70% ± 17% in the cluster center. We derive a tidal circularization period of ${P}_{\mathrm{circ}}={11.0}_{-1.0}^{+1.1}\,\mathrm{days}$ . We also analyze the incompleteness-corrected distributions of binary orbital elements and masses. The period distribution rises toward longer periods. The eccentricity distribution, beyond Pcirc, is consistent with a uniform distribution. The mass-ratio distribution is also consistent with a uniform distribution. Overall, these M67 binaries are closely consistent with similar binaries in the galactic field, as well as with the old (7 Gyr) open cluster NGC 188. WOCS. 83.
TIC 168789840: A Sextuply Eclipsing Sextuple Star SystemPowell, Brian P.Kostov, Veselin B.Rappaport, Saul A.Borkovits, TamásZasche, PetrTokovinin, AndreiKruse, EthanLatham, David W.Montet, Benjamin T.Jensen, Eric L. N.Jayaraman, RahulCollins, Karen A.Mašek, MartinHellier, CoelEvans, PhilTan, Thiam-GuanSchlieder, Joshua E.Torres, GuillermoSmale, Alan P.Friedman, Adam H.Barclay, ThomasGagliano, RobertQuintana, Elisa V.Jacobs, Thomas L.Gilbert, Emily A.Kristiansen, Martti H.Colón, Knicole D.LaCourse, Daryll M.Olmschenk, GregOmohundro, MarkSchnittman, Jeremy D.Schwengeler, Hans M.Barry, Richard K.Terentev, Ivan A.Boyd, PatriciaSchmitt, Allan R.Quinn, Samuel N.Vanderburg, AndrewPalle, EnricArmstrong, JamesRicker, George R.Vanderspek, RolandSeager, S.Winn, Joshua N.Jenkins, Jon M.Caldwell, Douglas A.Wohler, BillShiao, BernieBurke, Christopher J.Daylan, TansuVillaseñor, JoelDOI: info:10.3847/1538-3881/abddb5v. 161162
Powell, Brian P., Kostov, Veselin B., Rappaport, Saul A., Borkovits, Tamás, Zasche, Petr, Tokovinin, Andrei, Kruse, Ethan, Latham, David W., Montet, Benjamin T., Jensen, Eric L. N., Jayaraman, Rahul, Collins, Karen A., Mašek, Martin, Hellier, Coel, Evans, Phil, Tan, Thiam-Guan, Schlieder, Joshua E., Torres, Guillermo, Smale, Alan P., Friedman, Adam H., Barclay, Thomas, Gagliano, Robert, Quintana, Elisa V., Jacobs, Thomas L., Gilbert, Emily A. et al. 2021. "TIC 168789840: A Sextuply Eclipsing Sextuple Star System." The Astronomical Journal 161:162.
ID: 159318
Type: article
Authors: Powell, Brian P.; Kostov, Veselin B.; Rappaport, Saul A.; Borkovits, Tamás; Zasche, Petr; Tokovinin, Andrei; Kruse, Ethan; Latham, David W.; Montet, Benjamin T.; Jensen, Eric L. N.; Jayaraman, Rahul; Collins, Karen A.; Mašek, Martin; Hellier, Coel; Evans, Phil; Tan, Thiam-Guan; Schlieder, Joshua E.; Torres, Guillermo; Smale, Alan P.; Friedman, Adam H.; Barclay, Thomas; Gagliano, Robert; Quintana, Elisa V.; Jacobs, Thomas L.; Gilbert, Emily A.; Kristiansen, Martti H.; Colón, Knicole D.; LaCourse, Daryll M.; Olmschenk, Greg; Omohundro, Mark; Schnittman, Jeremy D.; Schwengeler, Hans M.; Barry, Richard K.; Terentev, Ivan A.; Boyd, Patricia; Schmitt, Allan R.; Quinn, Samuel N.; Vanderburg, Andrew; Palle, Enric; Armstrong, James; Ricker, George R.; Vanderspek, Roland; Seager, S.; Winn, Joshua N.; Jenkins, Jon M.; Caldwell, Douglas A.; Wohler, Bill; Shiao, Bernie; Burke, Christopher J.; Daylan, Tansu; Villaseñor, Joel
Abstract: We report the discovery of a sextuply eclipsing sextuple star system from TESS data, TIC 168789840, also known as TYC 7037-89-1, the first known sextuple system consisting of three eclipsing binaries. The target was observed in Sectors 4 and 5 during Cycle 1, with lightcurves extracted from TESS Full Frame Image data. It was also previously observed by the WASP survey and ASAS-SN. The system consists of three gravitationally bound eclipsing binaries in a hierarchical structure of an inner quadruple system with an outer binary subsystem. Follow-up observations from several different observatories were conducted as a means of determining additional parameters. The system was resolved by speckle interferometry with a 0"42 separation between the inner quadruple and outer binary, inferring an estimated outer period of ∼2 kyr. It was determined that the fainter of the two resolved components is an 8.217 day eclipsing binary, which orbits the inner quadruple that contains two eclipsing binaries with periods of 1.570 days and 1.306 days. Markov Chain Monte Carlo (MCMC) analysis of the stellar parameters has shown that the three binaries of TIC 168789840 are "triplets," as each binary is quite similar to the others in terms of mass, radius, and Teff. As a consequence of its rare composition, structure, and orientation, this object can provide important new insight into the formation, dynamics, and evolution of multiple star systems. Future observations could reveal if the intermediate and outer orbital planes are all aligned with the planes of the three inner eclipsing binaries.
Parallax Systematics and Photocenter Motions of Benchmark Eclipsing Binaries in Gaia EDR3Stassun, Keivan G.Torres, GuillermoDOI: info:10.3847/2041-8213/abdaadv. 907L33
Stassun, Keivan G. and Torres, Guillermo. 2021. "Parallax Systematics and Photocenter Motions of Benchmark Eclipsing Binaries in Gaia EDR3." The Astrophysical Journal 907:L33.
ID: 159630
Type: article
Authors: Stassun, Keivan G.; Torres, Guillermo
Abstract: Previous analyses of various standard candles observed by the Gaia satellite have reported statistically significant systematics in the parallaxes that have improved from ∼250 μas in the first data release (DR1) to 50-80 μas in the second data release (DR2). Here we examine the parallaxes newly reported in the Gaia early third data release (EDR3) using the same sample of benchmark eclipsing binaries (EBs) we used to assess the DR1 and DR2 parallaxes. We find a mean offset of -37 ± 20 μas (Gaia - EB), which decreases to -15 ± 18 μas after applying the corrections recommended by the Gaia Mission team; global systematics in the Gaia parallaxes have clearly improved and are no longer statistically significant for the EB sample, which spans 5 ≲ G ≲ 12 in brightness and 0.03-3 kpc in distance. We also find that the Renormalized Unit Weight Error (RUWE) goodness-of-fit statistic reported in Gaia DR3 is highly sensitive to unresolved companions (tertiaries in the case of our EB sample) as well as to photocenter motion of the binaries themselves. RUWE is nearly perfectly correlated (r2 = 0.82) with photocenter motions down to ≲0.1 mas, and surprisingly this correlation exists entirely within the nominal "good" RUWE range of 1.0-1.4. This suggests that RUWE values even slightly greater than 1.0 may signify unresolved binaries in Gaia, and that the RUWE value can serve as a quantitative predictor of the photocenter motion.
Identification of young nearby runaway stars based on Gaia data and the lithium test†Bischoff, RichardMugrauer, MarkusTorres, GuillermoHeyne, TheresaLux, OliverMunz, VeraNeuhäuser, RalphHoffmann, SusanneTrepanovski, AnjaDOI: info:10.1002/asna.202013793v. 341908–942
Bischoff, Richard, Mugrauer, Markus, Torres, Guillermo, Heyne, Theresa, Lux, Oliver, Munz, Vera, Neuhäuser, Ralph, Hoffmann, Susanne, and Trepanovski, Anja. 2020. "Identification of young nearby runaway stars based on Gaia data and the lithium test." Astronomische Nachrichten 341:908– 942.
ID: 158645
Type: article
Authors: Bischoff, Richard; Mugrauer, Markus; Torres, Guillermo; Heyne, Theresa; Lux, Oliver; Munz, Vera; Neuhäuser, Ralph; Hoffmann, Susanne; Trepanovski, Anja
Abstract: Young nearby runaway stars are suitable to search for their place of origin and possibly associated objects, for example, neutron stars. Tetzlaff et al. (2011) selected young (=50 Myr) runaway star candidates from Hipparcos, for which they had estimated the ages from the location in the Hertzsprung-Russell diagram and evolutionary models. Here, we redetermine or constrain their young ages more precisely, not only by using the new Gaia DR2 data but also by measuring lithium, which is a youth indicator. For 308 stars, we obtained spectra to search for the strong resonance doublet of the lithium-7 isotope at 6708 Å. The spectra were obtained with the Échelle spectrograph FLECHAS at the University Observatory Jena between February 2015 and June 2018 and with TRES between April 2011 and June 2017 at the Fred L. Whipple Observatory. We found 208 stars with a significant occurrence of lithium in their spectra, and 5 possess a possible age that is younger than or about 50 Myr. Three of these targets are even closer than GJ 182, the nearest known runaway star at about 24 pc. These stars are young runaway stars suitable for further investigation of their origin from either a dynamical or supernova ejection.
When Do Stalled Stars Resume Spinning Down? Advancing Gyrochronology with Ruprecht 147Curtis, Jason LeeAgüeros, Marcel A.Matt, Sean P.Covey, Kevin R.Douglas, Stephanie T.Angus, RuthSaar, Steven H.Cody, Ann MarieVanderburg, AndrewLaw, Nicholas M.Kraus, Adam L.Latham, David W.Baranec, ChristophRiddle, ReedZiegler, CarlLund, Mikkel N.Torres, GuillermoMeibom, SørenAguirre, Victor SilvaWright, Jason T.DOI: info:10.3847/1538-4357/abbf58v. 904140
Curtis, Jason Lee, Agüeros, Marcel A., Matt, Sean P., Covey, Kevin R., Douglas, Stephanie T., Angus, Ruth, Saar, Steven H., Cody, Ann Marie, Vanderburg, Andrew, Law, Nicholas M., Kraus, Adam L., Latham, David W., Baranec, Christoph, Riddle, Reed, Ziegler, Carl, Lund, Mikkel N., Torres, Guillermo, Meibom, Søren, Aguirre, Victor Silva, and Wright, Jason T. 2020. "When Do Stalled Stars Resume Spinning Down? Advancing Gyrochronology with Ruprecht 147." The Astrophysical Journal 904:140.
ID: 158796
Type: article
Authors: Curtis, Jason Lee; Agüeros, Marcel A.; Matt, Sean P.; Covey, Kevin R.; Douglas, Stephanie T.; Angus, Ruth; Saar, Steven H.; Cody, Ann Marie; Vanderburg, Andrew; Law, Nicholas M.; Kraus, Adam L.; Latham, David W.; Baranec, Christoph; Riddle, Reed; Ziegler, Carl; Lund, Mikkel N.; Torres, Guillermo; Meibom, Søren; Aguirre, Victor Silva; Wright, Jason T.
Abstract: Recent measurements of rotation periods ( ${P}_{\mathrm{rot}}$ ) in the benchmark open clusters Praesepe (670 Myr), NGC 6811 (1 Gyr), and NGC 752 (1.4 Gyr) demonstrate that, after converging onto a tight sequence of slowly rotating stars in mass–period space, stars temporarily stop spinning down. These data also show that the duration of this epoch of stalled spin-down increases toward lower masses. To determine when stalled stars resume spinning down, we use data from the K2 mission and the Palomar Transient Factory to measure ${P}_{\mathrm{rot}}$ for 58 dwarf members of the 2.7 Gyr old cluster Ruprecht 147, 39 of which satisfy our criteria designed to remove short-period or near-equal-mass binaries. Combined with the Kepler ${P}_{\mathrm{rot}}$ data for the approximately coeval cluster NGC 6819 (30 stars with M? > 0.85 ${M}_{\odot }$ ), our new measurements more than double the number of ?2.5 Gyr benchmark rotators and extend this sample down to ?0.55 ${M}_{\odot }$ . The slowly rotating sequence for this joint sample appears relatively flat (22 ± 2 days) compared to sequences for younger clusters. This sequence also intersects the Kepler intermediate-period gap, demonstrating that this gap was not created by a lull in star formation. We calculate the time at which stars resume spinning down and find that 0.55 ${M}_{\odot }$ stars remain stalled for at least 1.3 Gyr. To accurately age-date low-mass stars in the field, gyrochronology formulae must be modified to account for this stalling timescale. Empirically tuning a core–envelope coupling model with open cluster data can account for most of the apparent stalling effect. However, alternative explanations, e.g., a temporary reduction in the magnetic braking torque, cannot yet be ruled out.
TESS Spots a Hot Jupiter with an Inner Transiting NeptuneHuang, Chelsea X.Quinn, Samuel N.Vanderburg, AndrewBecker, JulietteRodriguez, Joseph E.Pozuelos, Francisco J.Gandolfi, DavideZhou, GeorgeMann, Andrew W.Collins, Karen A.Crossfield, IanBarkaoui, KhalidCollins, Kevin I.Fridlund, MalcolmGillon, MichaëlGonzales, Erica J.Günther, Maximilian N.Henry, Todd J.Howell, Steve B.James, Hodari-SadikiJao, Wei-ChunJehin, EmmanuëlJensen, Eric L. N.Kane, Stephen R.Lissauer, Jack J.Matthews, ElisabethMatson, Rachel A.Paredes, Leonardo A.Schlieder, Joshua E.Stassun, Keivan G.Shporer, AviSha, LizhouTan, Thiam-GuanGeorgieva, IskraMathur, SavitaPalle, EnricPersson, Carina M.Eylen, Vincent VanRicker, George R.Vanderspek, Roland K.Latham, David W.Winn, Joshua N.Seager, S.Jenkins, Jon M.Burke, Christopher J.Goeke, Robert F.Rinehart, StephenRose, Mark E.Ting, Eric B.Torres, GuillermoWong, IanDOI: info:10.3847/2041-8213/ab7302v. 892L7
Huang, Chelsea X., Quinn, Samuel N., Vanderburg, Andrew, Becker, Juliette, Rodriguez, Joseph E., Pozuelos, Francisco J., Gandolfi, Davide, Zhou, George, Mann, Andrew W., Collins, Karen A., Crossfield, Ian, Barkaoui, Khalid, Collins, Kevin I., Fridlund, Malcolm, Gillon, Michaël, Gonzales, Erica J., Günther, Maximilian N., Henry, Todd J., Howell, Steve B., James, Hodari-Sadiki, Jao, Wei-Chun, Jehin, Emmanuël, Jensen, Eric L. N., Kane, Stephen R., Lissauer, Jack J. et al. 2020. "TESS Spots a Hot Jupiter with an Inner Transiting Neptune." The Astrophysical Journal 892:L7.
ID: 156380
Type: article
Authors: Huang, Chelsea X.; Quinn, Samuel N.; Vanderburg, Andrew; Becker, Juliette; Rodriguez, Joseph E.; Pozuelos, Francisco J.; Gandolfi, Davide; Zhou, George; Mann, Andrew W.; Collins, Karen A.; Crossfield, Ian; Barkaoui, Khalid; Collins, Kevin I.; Fridlund, Malcolm; Gillon, Michaël; Gonzales, Erica J.; Günther, Maximilian N.; Henry, Todd J.; Howell, Steve B.; James, Hodari-Sadiki; Jao, Wei-Chun; Jehin, Emmanuël; Jensen, Eric L. N.; Kane, Stephen R.; Lissauer, Jack J.; Matthews, Elisabeth; Matson, Rachel A.; Paredes, Leonardo A.; Schlieder, Joshua E.; Stassun, Keivan G.; Shporer, Avi; Sha, Lizhou; Tan, Thiam-Guan; Georgieva, Iskra; Mathur, Savita; Palle, Enric; Persson, Carina M.; Eylen, Vincent Van; Ricker, George R.; Vanderspek, Roland K.; Latham, David W.; Winn, Joshua N.; Seager, S.; Jenkins, Jon M.; Burke, Christopher J.; Goeke, Robert F.; Rinehart, Stephen; Rose, Mark E.; Ting, Eric B.; Torres, Guillermo; Wong, Ian
Abstract: Hot Jupiters are rarely accompanied by other planets within a factor of a few in orbital distance. Previously, only two such systems have been found. Here, we report the discovery of a third system using data from the Transiting Exoplanet Survey Satellite (TESS). The host star, TOI-1130, is an eleventh magnitude K-dwarf in Gaia G-band. It has two transiting planets: a Neptune-sized planet (3.65 ± 0.10 R\oplus) with a 4.1 days period, and a hot Jupiter (1.50-0.22+0.27 RJ) with an 8.4 days period. Precise radial-velocity observations show that the mass of the hot Jupiter is 0.974-0.044+0.043 MJ. For the inner Neptune, the data provide only an upper limit on the mass of 0.17 MJ (3σ). Nevertheless, we are confident that the inner planet is real, based on follow-up ground-based photometry and adaptive-optics imaging that rule out other plausible sources of the TESS transit signal. The unusual planetary architecture of and the brightness of the host star make TOI-1130 a good test case for planet formation theories, and an attractive target for future spectroscopic observations.
TOI-1338: TESS' First Transiting Circumbinary PlanetKostov, Veselin B.Orosz, Jerome A.Feinstein, Adina D.Welsh, William F.Cukier, WolfHaghighipour, NaderQuarles, BillyMartin, David V.Montet, Benjamin T.Torres, GuillermoTriaud, Amaury H. M. J.Barclay, ThomasBoyd, PatriciaBriceno, CesarCameron, Andrew CollierCorreia, Alexandre C. M.Gilbert, Emily A.Gill, SamuelGillon, MichaëlHaqq-Misra, JacobHellier, CoelDressing, CourtneyFabrycky, Daniel C.Furesz, GaborJenkins, Jon M.Kane, Stephen R.Kopparapu, RaviHodžić, Vedad KunovacLatham, David W.Law, NicholasLevine, Alan M.Li, GongjieLintott, ChrisLissauer, Jack J.Mann, Andrew W.Mazeh, TseviMardling, RosemaryMaxted, Pierre F. L.Eisner, NoraPepe, FrancescoPepper, JoshuaPollacco, DonQuinn, Samuel N.Quintana, Elisa V.Rowe, Jason F.Ricker, GeorgeRose, Mark E.Seager, S.Santerne, AlexandreSégransan, DamienShort, Donald R.Smith, Jeffrey C.Standing, Matthew R.Tokovinin, AndreiTrifonov, TrifonTurner, OliverTwicken, Joseph D.Udry, StéphaneVanderspek, RolandWinn, Joshua N.Wolf, Eric T.Ziegler, CarlAnsorge, PeterBarnet, FrankBergeron, JoelHuten, MarcPappa, Giuseppevan der Straeten, TimoDOI: info:10.3847/1538-3881/ab8a48v. 159253
Kostov, Veselin B., Orosz, Jerome A., Feinstein, Adina D., Welsh, William F., Cukier, Wolf, Haghighipour, Nader, Quarles, Billy, Martin, David V., Montet, Benjamin T., Torres, Guillermo, Triaud, Amaury H. M. J., Barclay, Thomas, Boyd, Patricia, Briceno, Cesar, Cameron, Andrew Collier, Correia, Alexandre C. M., Gilbert, Emily A., Gill, Samuel, Gillon, Michaël, Haqq-Misra, Jacob, Hellier, Coel, Dressing, Courtney, Fabrycky, Daniel C., Furesz, Gabor, Jenkins, Jon M. et al. 2020. "TOI-1338: TESS' First Transiting Circumbinary Planet." The Astronomical Journal 159:253.
ID: 156875
Type: article
Authors: Kostov, Veselin B.; Orosz, Jerome A.; Feinstein, Adina D.; Welsh, William F.; Cukier, Wolf; Haghighipour, Nader; Quarles, Billy; Martin, David V.; Montet, Benjamin T.; Torres, Guillermo; Triaud, Amaury H. M. J.; Barclay, Thomas; Boyd, Patricia; Briceno, Cesar; Cameron, Andrew Collier; Correia, Alexandre C. M.; Gilbert, Emily A.; Gill, Samuel; Gillon, Michaël; Haqq-Misra, Jacob; Hellier, Coel; Dressing, Courtney; Fabrycky, Daniel C.; Furesz, Gabor; Jenkins, Jon M.; Kane, Stephen R.; Kopparapu, Ravi; Hodžić, Vedad Kunovac; Latham, David W.; Law, Nicholas; Levine, Alan M.; Li, Gongjie; Lintott, Chris; Lissauer, Jack J.; Mann, Andrew W.; Mazeh, Tsevi; Mardling, Rosemary; Maxted, Pierre F. L.; Eisner, Nora; Pepe, Francesco; Pepper, Joshua; Pollacco, Don; Quinn, Samuel N.; Quintana, Elisa V.; Rowe, Jason F.; Ricker, George; Rose, Mark E.; Seager, S.; Santerne, Alexandre; Ségransan, Damien; Short, Donald R.; Smith, Jeffrey C.; Standing, Matthew R.; Tokovinin, Andrei; Trifonov, Trifon; Turner, Oliver; Twicken, Joseph D.; Udry, Stéphane; Vanderspek, Roland; Winn, Joshua N.; Wolf, Eric T.; Ziegler, Carl; Ansorge, Peter; Barnet, Frank; Bergeron, Joel; Huten, Marc; Pappa, Giuseppe; van der Straeten, Timo
Abstract: We report the detection of the first circumbinary planet (CBP) found by Transiting Exoplanet Survey Satellite (TESS). The target, a known eclipsing binary, was observed in sectors 1 through 12 at 30 minute cadence and in sectors 4 through 12 at 2 minute cadence. It consists of two stars with masses of 1.1 M and 0.3 M on a slightly eccentric (0.16), 14.6 day orbit, producing prominent primary eclipses and shallow secondary eclipses. The planet has a radius of ∼6.9 R and was observed to make three transits across the primary star of roughly equal depths (∼0.2%) but different durations-a common signature of transiting CBPs. Its orbit is nearly circular (e ≍ 0.09) with an orbital period of 95.2 days. The orbital planes of the binary and the planet are aligned to within ∼1°. To obtain a complete solution for the system, we combined the TESS photometry with existing ground- based radial-velocity observations in a numerical photometric-dynamical model. The system demonstrates the discovery potential of TESS for CBPs and provides further understanding of the formation and evolution of planets orbiting close binary stars.
TESS Hunt for Young and Maturing Exoplanets (THYME). III. A Two-planet System in the 400 Myr Ursa Major GroupMann, Andrew W.Johnson, Marshall C.Vanderburg, AndrewKraus, Adam L.Rizzuto, Aaron C.Wood, Mackenna L.Bush, Jonathan L.Rockcliffe, KeighleyNewton, Elisabeth R.Latham, David W.Mamajek, Eric E.Zhou, GeorgeQuinn, Samuel N.Thao, Pa ChiaBenatti, SerenaCosentino, RosarioDesidera, SilvanoHarutyunyan, AvetLovis, ChristopheMortier, AnneliesPepe, Francesco A.Poretti, EnnioWilson, Thomas G.Kristiansen, Martti H.Gagliano, RobertJacobs, ThomasLaCourse, Daryll M.Omohundro, MarkSchwengeler, Hans MartinTerentev, Ivan A.Kane, Stephen R.Hill, Michelle L.Rabus, MarkusEsquerdo, Gilbert A.Berlind, PerryCollins, Karen A.Murawski, GabrielSallam, Nezar HazamAitken, Michael M.Massey, BobRicker, George R.Vanderspek, RolandSeager, SaraWinn, Joshua N.Jenkins, Jon M.Barclay, ThomasCaldwell, Douglas A.Dragomir, DianaDoty, John P.Glidden, AnaTenenbaum, PeterTorres, GuillermoTwicken, Joseph D.Villanueva, Steven, Jr.DOI: info:10.3847/1538-3881/abae64v. 160179
Mann, Andrew W., Johnson, Marshall C., Vanderburg, Andrew, Kraus, Adam L., Rizzuto, Aaron C., Wood, Mackenna L., Bush, Jonathan L., Rockcliffe, Keighley, Newton, Elisabeth R., Latham, David W., Mamajek, Eric E., Zhou, George, Quinn, Samuel N., Thao, Pa Chia, Benatti, Serena, Cosentino, Rosario, Desidera, Silvano, Harutyunyan, Avet, Lovis, Christophe, Mortier, Annelies, Pepe, Francesco A., Poretti, Ennio, Wilson, Thomas G., Kristiansen, Martti H., Gagliano, Robert et al. 2020. "TESS Hunt for Young and Maturing Exoplanets (THYME). III. A Two-planet System in the 400 Myr Ursa Major Group." The Astronomical Journal 160:179.
ID: 157597
Type: article
Authors: Mann, Andrew W.; Johnson, Marshall C.; Vanderburg, Andrew; Kraus, Adam L.; Rizzuto, Aaron C.; Wood, Mackenna L.; Bush, Jonathan L.; Rockcliffe, Keighley; Newton, Elisabeth R.; Latham, David W.; Mamajek, Eric E.; Zhou, George; Quinn, Samuel N.; Thao, Pa Chia; Benatti, Serena; Cosentino, Rosario; Desidera, Silvano; Harutyunyan, Avet; Lovis, Christophe; Mortier, Annelies; Pepe, Francesco A.; Poretti, Ennio; Wilson, Thomas G.; Kristiansen, Martti H.; Gagliano, Robert; Jacobs, Thomas; LaCourse, Daryll M.; Omohundro, Mark; Schwengeler, Hans Martin; Terentev, Ivan A.; Kane, Stephen R.; Hill, Michelle L.; Rabus, Markus; Esquerdo, Gilbert A.; Berlind, Perry; Collins, Karen A.; Murawski, Gabriel; Sallam, Nezar Hazam; Aitken, Michael M.; Massey, Bob; Ricker, George R.; Vanderspek, Roland; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Barclay, Thomas; Caldwell, Douglas A.; Dragomir, Diana; Doty, John P.; Glidden, Ana; Tenenbaum, Peter; Torres, Guillermo; Twicken, Joseph D.; Villanueva, Steven, Jr.
Abstract: Exoplanets can evolve significantly between birth and maturity, as their atmospheres, orbits, and structures are shaped by their environment. Young planets ( and 2.67 ± 0.12 R, the orbital periods are 7.11 and 20.55 days, and the orbital eccentricities are lower than about 0.2. Using High Accuracy Radial velocity Planet Searcher for the Northern hemisphere velocities, we measure the Rossiter-McLaughlin signal of the inner planet, demonstrating that the orbit is prograde. Since the host star is bright (V = 6.9), both planets are amenable to transmission spectroscopy, radial velocity measurements of their masses, and more precise determination of the stellar obliquity. This system is therefore poised to play an important role in our understanding of planetary system evolution in the first billion years after formation.
The TESS light curve of AI PhoenicisMaxted, P. F. L.Gaulme, PatrickGraczyk, D.Hełminiak, K. G.Johnston, C.Orosz, Jerome A.Prša, AndrejSouthworth, JohnTorres, GuillermoDavies, Guy R.Ball, WarrickChaplin, William J.DOI: info:10.1093/mnras/staa1662v. 498332–343
Maxted, P. F. L., Gaulme, Patrick, Graczyk, D., Hełminiak, K. G., Johnston, C., Orosz, Jerome A., Prša, Andrej, Southworth, John, Torres, Guillermo, Davies, Guy R., Ball, Warrick, and Chaplin, William J. 2020. "The TESS light curve of AI Phoenicis." Monthly Notices of the Royal Astronomical Society 498:332– 343.
ID: 157768
Type: article
Authors: Maxted, P. F. L.; Gaulme, Patrick; Graczyk, D.; Hełminiak, K. G.; Johnston, C.; Orosz, Jerome A.; Prša, Andrej; Southworth, John; Torres, Guillermo; Davies, Guy R.; Ball, Warrick; Chaplin, William J.
Abstract: Accurate masses and radii for normal stars derived from observations of detached eclipsing binary stars are of fundamental importance for testing stellar models and may be useful for calibrating free parameters in these model if the masses and radii are sufficiently precise and accurate. We aim to measure precise masses and radii for the stars in the bright eclipsing binary AI Phe, and to quantify the level of systematic error in these estimates. We use several different methods to model the Transiting Exoplanet Survey Satellite (TESS) light curve of AI Phe combined with spectroscopic orbits from multiple sources to estimate precisely the stellar masses and radii together with robust error estimates. We find that the agreement between different methods for the light-curve analysis is very good but some methods underestimate the errors on the model parameters. The semi-amplitudes of the spectroscopic orbits derived from spectra obtained with modern échelle spectrographs are consistent to within 0.1 per cent. The masses of the stars in AI Phe are $M_1 = 1.1938 \pm 0.0008\, \rm M_{\odot }$ and $M_2 = 1.2438 \pm 0.0008\, \rm M_{\odot }$ , and the radii are $R_1 = 1.8050 \pm 0.0022\, \rm R_{\odot }$ and $R_2 = 2.9332 \pm 0.0023\, \rm R_{\odot }$ . We conclude that it is possible to measure accurate masses and radii for stars in bright eclipsing binary stars to a precision of 0.2 per cent or better using photometry from TESS and spectroscopy obtained with modern échelle spectrographs. We provide recommendations for publishing masses and radii of eclipsing binary stars at this level of precision.
Kepler-1661 b: A Neptune-sized Kepler Transiting Circumbinary Planet around a Grazing Eclipsing BinarySocia, Quentin J.Welsh, William F.Orosz, Jerome A.Cochran, William D.Endl, MichaelQuarles, BillyShort, Donald R.Torres, GuillermoWindmiller, GurYenawine, MitchellDOI: info:10.3847/1538-3881/ab665bv. 15994
Socia, Quentin J., Welsh, William F., Orosz, Jerome A., Cochran, William D., Endl, Michael, Quarles, Billy, Short, Donald R., Torres, Guillermo, Windmiller, Gur, and Yenawine, Mitchell. 2020. "Kepler-1661 b: A Neptune-sized Kepler Transiting Circumbinary Planet around a Grazing Eclipsing Binary." The Astronomical Journal 159:94.
ID: 156464
Type: article
Authors: Socia, Quentin J.; Welsh, William F.; Orosz, Jerome A.; Cochran, William D.; Endl, Michael; Quarles, Billy; Short, Donald R.; Torres, Guillermo; Windmiller, Gur; Yenawine, Mitchell
Abstract: We report the discovery of a Neptune-sized ( ${R}_{p}=3.87\pm 0.06{R}_{\oplus }$ ) transiting circumbinary planet, Kepler-1661 b, found in the Kepler photometry. The planet has a period of ∼175 days and its orbit precesses with a period of only 35 yr. The precession causes the alignment of the orbital planes to vary, and the planet is in a transiting configuration only ∼7% of the time as seen from Earth. As with several other Kepler circumbinary planets, Kepler-1661 b orbits close to the stability radius, and is near the (hot) edge of the habitable zone. The planet orbits a single-lined, grazing eclipsing binary, containing a 0.84 ${M}_{\odot }$ and 0.26 ${M}_{\odot }$ pair of stars in a mildly eccentric (e = 0.11), 28.2 day orbit. The system is fairly young, with an estimated age of ∼1─3 Gyr, and exhibits significant starspot modulations. The grazing eclipse configuration means the system is very sensitive to changes in the binary inclination, which manifests itself as a change in the eclipse depth. The starspots contaminate the eclipse photometry, but not in the usual way of inducing spurious eclipse timing variations. Rather, the starspots alter the normalization of the light curve, and hence the eclipse depths. This can lead to spurious eclipse depth variations, which are then incorrectly ascribed to binary orbital precession.
TESS Reveals a Short-period Sub-Neptune Sibling (HD 86226c) to a Known Long-period Giant PlanetTeske, JohannaDíaz, Matías R.Luque, RafaelMočnik, TeoSeidel, Julia V.Otegi, Jon FernándezFeng, FaboJenkins, James S.Pallè, EnricSégransan, DamienUdry, StèphaneCollins, Karen A.Eastman, Jason D.Ricker, George R.Vanderspek, RolandLatham, David W.Seager, SaraWinn, Joshua N.Jenkins, Jon M.Anderson, David R.Barclay, ThomasBouchy, FrançoisBurt, Jennifer A.Butler, R. PaulCaldwell, Douglas A.Collins, Kevin I.Crane, Jeffrey D.Dorn, CarolineFlowers, ErinHaldemann, JonasHelled, RavitHellier, CoelJensen, Eric L. N.Kane, Stephen R.Law, NicholasLissauer, Jack J.Mann, Andrew W.Marmier, MaximeNielsen, Louise DyregaardRose, Mark E.Shectman, Stephen A.Shporer, AviTorres, GuillermoWang, Sharon X.Wolfgang, AngieWong, IanZiegler, CarlDOI: info:10.3847/1538-3881/ab9f95v. 16096
Teske, Johanna, Díaz, Matías R., Luque, Rafael, Močnik, Teo, Seidel, Julia V., Otegi, Jon Fernández, Feng, Fabo, Jenkins, James S., Pallè, Enric, Ségransan, Damien, Udry, Stèphane, Collins, Karen A., Eastman, Jason D., Ricker, George R., Vanderspek, Roland, Latham, David W., Seager, Sara, Winn, Joshua N., Jenkins, Jon M., Anderson, David R., Barclay, Thomas, Bouchy, François, Burt, Jennifer A., Butler, R. Paul, Caldwell, Douglas A. et al. 2020. "TESS Reveals a Short-period Sub-Neptune Sibling (HD 86226c) to a Known Long-period Giant Planet." The Astronomical Journal 160:96.
ID: 157770
Type: article
Authors: Teske, Johanna; Díaz, Matías R.; Luque, Rafael; Močnik, Teo; Seidel, Julia V.; Otegi, Jon Fernández; Feng, Fabo; Jenkins, James S.; Pallè, Enric; Ségransan, Damien; Udry, Stèphane; Collins, Karen A.; Eastman, Jason D.; Ricker, George R.; Vanderspek, Roland; Latham, David W.; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Anderson, David R.; Barclay, Thomas; Bouchy, François; Burt, Jennifer A.; Butler, R. Paul; Caldwell, Douglas A.; Collins, Kevin I.; Crane, Jeffrey D.; Dorn, Caroline; Flowers, Erin; Haldemann, Jonas; Helled, Ravit; Hellier, Coel; Jensen, Eric L. N.; Kane, Stephen R.; Law, Nicholas; Lissauer, Jack J.; Mann, Andrew W.; Marmier, Maxime; Nielsen, Louise Dyregaard; Rose, Mark E.; Shectman, Stephen A.; Shporer, Avi; Torres, Guillermo; Wang, Sharon X.; Wolfgang, Angie; Wong, Ian; Ziegler, Carl
Abstract: The Transiting Exoplanet Survey Satellite mission was designed to find transiting planets around bright, nearby stars. Here, we present the detection and mass measurement of a small, short-period (≍4 days) transiting planet around the bright (V = 7.9), solar-type star HD 86226 (TOI-652, TIC 22221375), previously known to host a long-period (∼1600 days) giant planet. HD 86226c (TOI-652.01) has a radius of 2.16 ± 0.08 R and a mass of ${7.25}_{-1.12}^{+1.19}$ M, based on archival and new radial velocity data. We also update the parameters of the longer-period, not-known-to-transit planet, and find it to be less eccentric and less massive than previously reported. The density of the transiting planet is 3.97 g cm-3, which is low enough to suggest that the planet has at least a small volatile envelope, but the mass fractions of rock, iron, and water are not well-constrained. Given the host star brightness, planet period, and location of the planet near both the "radius gap" and the "hot Neptune desert," HD 86226c is an interesting candidate for transmission spectroscopy to further refine its composition. * This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.
Spectroscopic Monitoring of Rapidly Rotating Early-type Stars in the Pleiades ClusterTorres, GuillermoDOI: info:10.3847/1538-4357/abb136v. 90191
Torres, Guillermo. 2020. "Spectroscopic Monitoring of Rapidly Rotating Early-type Stars in the Pleiades Cluster." The Astrophysical Journal 901:91.
ID: 157588
Type: article
Authors: Torres, Guillermo
Abstract: Radial velocities for the early-type stars in the Pleiades cluster have always been challenging to measure because of the significant rotational broadening of the spectral lines. The large scatter in published velocities has led to claims that many are spectroscopic binaries, and in several cases, preliminary orbital solutions have been proposed. To investigate these claims, we obtained and report here velocity measurements for 33 rapidly rotating B, A, and early F stars in the Pleiades region, improving significantly on the precision of the historical velocities for most objects. With one or two exceptions, we do not confirm any of the previous claims of variability, and we also rule out all four of the previously published orbital solutions, for HD 22637, HD 23302, HD 23338, and HD 23410. We do find HD 22637 to be a binary but with a different period (71.8 days). HD 23338 is likely a binary as well, with a preliminary 8.7 yr period also different from the one published. Additionally, we report a 3635 day orbit for HD 24899, another new spectroscopic binary in the cluster. From the 32 bona fide members in our sample, we determine a mean radial velocity for the Pleiades of $5.79\pm 0.24\,\mathrm{km}\,{{\rm{s}}}^{-1}$ , or $5.52\pm 0.31\,\mathrm{km}\,{{\rm{s}}}^{-1}$ when objects with known visual companions are excluded. Adding these astrometric binaries to the new spectroscopic ones, we find a lower limit to the binary fraction among the B and A stars of 37%. In addition to the velocities, we measure $v\sin i$ for all stars, ranging between 69 and 317 $\mathrm{km}\,{{\rm{s}}}^{-1}$ .
Absolute Dimensions of the Unevolved F-type Eclipsing Binary BT VulpeculaeTorres, GuillermoLacy, Claud H. SandbergFekel, Francis C.Muterspaugh, Matthew W.DOI: info:10.3847/1538-4357/ab85c6v. 89496
Torres, Guillermo, Lacy, Claud H. Sandberg, Fekel, Francis C., and Muterspaugh, Matthew W. 2020. "Absolute Dimensions of the Unevolved F-type Eclipsing Binary BT Vulpeculae." The Astrophysical Journal 894:96.
ID: 156971
Type: article
Authors: Torres, Guillermo; Lacy, Claud H. Sandberg; Fekel, Francis C.; Muterspaugh, Matthew W.
Abstract: We report extensive differential V-band photometry and high-resolution spectroscopy for the 1.14 day, detached, double-lined eclipsing binary BT Vul (F0+F7). Our radial-velocity monitoring and light-curve analysis lead to absolute masses and radii of ${M}_{1}=1.5439\pm 0.0098\,{{ \mathcal M }}_{\odot }^{{\rm{N}}}$ and ${R}_{1}=1.536\pm 0.018\,{{ \mathcal R }}_{\odot }^{{\rm{N}}}$ for the primary, and ${M}_{2}=1.2196\pm 0.0080\,{{ \mathcal M }}_{\odot }^{{\rm{N}}}$ and ${R}_{2}=1.151\pm 0.029\,{{ \mathcal R }}_{\odot }^{{\rm{N}}}$ for the secondary. The effective temperatures are 7270 ± 150 K and 6260 ± 180 K, respectively. Both stars are rapid rotators, and the orbit is circular. A comparison with stellar evolution models from the MESA Isochrones and Stellar Tracks series shows excellent agreement with these determinations, for a composition of $[\mathrm{Fe}/{\rm{H}}]=+0.08$ and an age of 350 Myr. The two components of BT Vul are very near the zero- age main sequence.
Dynamical Masses for the Pleiades Binary System HII-2147Torres, GuillermoMelis, CarlKraus, Adam L.Dupuy, Trent J.Chilcote, Jeffrey K.Crepp, Justin R.DOI: info:10.3847/1538-4357/ab9c20v. 8982
Torres, Guillermo, Melis, Carl, Kraus, Adam L., Dupuy, Trent J., Chilcote, Jeffrey K., and Crepp, Justin R. 2020. "Dynamical Masses for the Pleiades Binary System HII-2147." The Astrophysical Journal 898:2.
ID: 157767
Type: article
Authors: Torres, Guillermo; Melis, Carl; Kraus, Adam L.; Dupuy, Trent J.; Chilcote, Jeffrey K.; Crepp, Justin R.
Abstract: We report our long-term spectroscopic monitoring of the Pleiades member HII-2147, which was previously spatially resolved at radio wavelengths in very long baseline interferometry (VLBI) observations. It has also been claimed to be a (presumably short-period) double-lined spectroscopic binary with relatively sharp lines, although no orbit has ever been published. Examination of our new spectroscopic material and the historical radial velocities shows that the current and previous spectra are best interpreted as featuring only a single set of lines of a moderately rapidly rotating star with slowly variable radial velocity, which is one of the sources detected by VLBI. We combine our own and other velocities with the VLBI measurements and new adaptive optics observations to derive the first astrometric-spectroscopic orbit of the G5 + G9 pair, with a period of 18.18 ± 0.11 yr. We infer dynamical masses of 0.897 ± 0.022 M for the spectroscopically visible star and 0.978 ± 0.024 M for the other, along with a distance of ${136.78}_{-0.46}^{+0.50}$ pc. The lack of detection of the lines of the more massive component in our spectra can be adequately explained if it is rotating much more rapidly than the star we see. This is consistent with the observation that the lines of the secondary are shallower than expected for a star of its spectral type.
Eclipsing Binaries in the Open Cluster Ruprecht 147. III. The Triple System EPIC 219552514 at the Main-sequence TurnoffTorres, GuillermoVanderburg, AndrewCurtis, Jason L.Kraus, Adam L.Rizzuto, Aaron C.Ireland, Michael J.DOI: info:10.3847/1538-4357/ab911bv. 896162
Torres, Guillermo, Vanderburg, Andrew, Curtis, Jason L., Kraus, Adam L., Rizzuto, Aaron C., and Ireland, Michael J. 2020. "Eclipsing Binaries in the Open Cluster Ruprecht 147. III. The Triple System EPIC 219552514 at the Main-sequence Turnoff." The Astrophysical Journal 896:162.
ID: 157769
Type: article
Authors: Torres, Guillermo; Vanderburg, Andrew; Curtis, Jason L.; Kraus, Adam L.; Rizzuto, Aaron C.; Ireland, Michael J.
Abstract: Spectroscopic observations are reported for the 2.75 day, double-lined, detached eclipsing binary EPIC 219552514 located at the turnoff of the old nearby open cluster Ruprecht 147. A joint analysis of our radial-velocity measurements and the K2 light curve leads to masses of ${M}_{1}={1.509}_{-0.056}^{+0.063}\,{M}_{\odot }$ and ${M}_{2}={0.649}_{-0.014}^{+0.015}\,{M}_{\odot }$ for the primary and secondary, along with radii of ${R}_{1}={2.505}_{-0.031}^{+0.026}\,{R}_{\odot }$ and ${R}_{2}={0.652}_{-0.012}^{+0.013}\,{R}_{\odot }$ , respectively. The effective temperatures are 6180 ± 100 K for the F7 primary and 4010 ± 170 K for the late K secondary. The orbit is circular, and the stars' rotation appears to be synchronized with the orbital motion. This is the third eclipsing system analyzed in the same cluster, following our earlier studies of EPIC 219394517 and EPIC 219568666. By comparison with stellar evolution models from the PARSEC series, we infer an age of ${2.67}_{-0.55}^{+0.39}$ Gyr that is consistent with the estimates for the other two systems. EPIC 219552514 is a hierarchical triple system, with the period of the slightly eccentric outer orbit being 463 days. The unseen tertiary is either a low-mass M dwarf or a white dwarf.
The Dependence of Convective Core Overshooting on Stellar Mass: Reality Check and Additional EvidenceClaret, AntonioTorres, GuillermoDOI: info:10.3847/1538-4357/ab1589v. 876134
Claret, Antonio and Torres, Guillermo. 2019. "The Dependence of Convective Core Overshooting on Stellar Mass: Reality Check and Additional Evidence." The Astrophysical Journal 876:134.
ID: 151865
Type: article
Authors: Claret, Antonio; Torres, Guillermo
Abstract: Overshooting from the convective cores of stars more massive than about 1.2 M has a profound impact on their subsequent evolution. And yet, the formulation of the overshooting mechanism in current stellar evolution models has a free parameter ({f}ov} in the diffusive approximation) that remains poorly constrained by observations, affecting the determination of astrophysically important quantities such as stellar ages. In an earlier series of papers, we assembled a sample of 37 well-measured detached eclipsing binaries to calibrate the dependence of {f}ov} on stellar mass, showing that it increases sharply up to a mass of roughly 2 M , and remains constant thereafter out to at least 4.4 M . Recent claims have challenged the utility of eclipsing binaries for this purpose, on the basis that the uncertainties in {f}ov} from the model fits are typically too large to be useful, casting doubt on a dependence of overshooting on mass. Here we reexamine those claims and show them to be too pessimistic, mainly because they did not account for all available constraints—both observational and theoretical—in assessing the true uncertainties. We also take the opportunity to add semiempirical {f}ov} determinations for 13 additional binaries to our previous sample, and to update the values for 9 others. All are consistent with and strengthen our previous conclusions, supporting a dependence of {f}ov} on mass that is now based on estimates for a total of 50 binary systems (100 stars).
Characterization of the L 98-59 multi-planetary system with HARPS. Mass characterization of a hot super-Earth, a sub-Neptune, and a mass upper limit on the third planetCloutier, RyanAstudillo-Defru, N.Bonfils, X.Jenkins, J. S.Berdiñas, Z.Ricker, G.Vanderspek, R.Latham, David W.Seager, S.Winn, J.Jenkins, J. M.Almenara, J. M.Bouchy, F.Delfosse, X.Díaz, M. R.Díaz, R. F.Doyon, R.Figueira, P.Forveille, T.Kurtovic, N. T.Lovis, C.Mayor, M.Menou, K.Morgan, E.Morris, R.Muirhead, P.Murgas, F.Pepe, F.Santos, N. C.Ségransan, D.Smith, J. C.Tenenbaum, P.Torres, GuillermoUdry, S.Vezie, M.Villasenor, J.DOI: info:10.1051/0004-6361/201935957v. 629A111
Cloutier, Ryan, Astudillo-Defru, N., Bonfils, X., Jenkins, J. S., Berdiñas, Z., Ricker, G., Vanderspek, R., Latham, David W., Seager, S., Winn, J., Jenkins, J. M., Almenara, J. M., Bouchy, F., Delfosse, X., Díaz, M. R., Díaz, R. F., Doyon, R., Figueira, P., Forveille, T., Kurtovic, N. T., Lovis, C., Mayor, M., Menou, K., Morgan, E., Morris, R. et al. 2019. "Characterization of the L 98-59 multi-planetary system with HARPS. Mass characterization of a hot super-Earth, a sub-Neptune, and a mass upper limit on the third planet." Astronomy and Astrophysics 629:A111.
ID: 154434
Type: article
Authors: Cloutier, Ryan; Astudillo-Defru, N.; Bonfils, X.; Jenkins, J. S.; Berdiñas, Z.; Ricker, G.; Vanderspek, R.; Latham, David W.; Seager, S.; Winn, J.; Jenkins, J. M.; Almenara, J. M.; Bouchy, F.; Delfosse, X.; Díaz, M. R.; Díaz, R. F.; Doyon, R.; Figueira, P.; Forveille, T.; Kurtovic, N. T.; Lovis, C.; Mayor, M.; Menou, K.; Morgan, E.; Morris, R.; Muirhead, P.; Murgas, F.; Pepe, F.; Santos, N. C.; Ségransan, D.; Smith, J. C.; Tenenbaum, P.; Torres, Guillermo; Udry, S.; Vezie, M.; Villasenor, J.
Abstract: Aims: L 98-59 (TIC 307210830, TOI-175) is a nearby M3 dwarf around which TESS revealed three small transiting planets (0.80, 1.35, 1.57 Earth radii) in a compact configuration with orbital periods shorter than 7.5 days. Here we aim to measure the masses of the known transiting planets in this system using precise radial velocity (RV) measurements taken with the HARPS spectrograph. Methods: We considered both trained and untrained Gaussian process regression models of stellar activity, which are modeled simultaneously with the planetary signals. Our RV analysis was then supplemented with dynamical simulations to provide strong constraints on the planets' orbital eccentricities by requiring long-term stability. Results: We measure the planet masses of the two outermost planets to be 2.42 ± 0.35 and 2.31 ± 0.46 Earth masses, which confirms the bulk terrestrial composition of the former and eludes to a significant radius fraction in an extended gaseous envelope for the latter. We are able to place an upper limit on the mass of the smallest, innermost planet of ( or via bin/cat/J/A+A/629/A111Based on observations made with the HARPS instrument on the ESO 3.6 m telescope under the program IDs 198.C-0838(A), 1102.C-0339(A), 0102.C-0525, and 0102.D-0483(A) at Cerro La Silla (Chile).
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.
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.
The Transiting Multi-planet System HD15337: Two Nearly Equal-mass Planets Straddling the Radius GapGandolfi, DavideFossati, LucaLivingston, John H.Stassun, Keivan G.Grziwa, SaschaBarragán, OscarFridlund, MalcolmKubyshkina, DariaPersson, Carina M.Dai, FeiLam, Kristine W. F.Albrecht, SimonBatalha, NatalieBeck, Paul G.Justesen, Anders BoCabrera, JuanCartwright, ScottCochran, William D.Csizmadia, SzilardDavies, Misty D.Deeg, Hans J.Eigmüller, PhilippEndl, MichaelErikson, AndersEsposito, MassimilianoGarcía, Rafael A.Goeke, RobertGonzález-Cuesta, LucíaGuenther, Eike W.Hatzes, Artie P.Hidalgo, DiegoHirano, TeruyukiHjorth, MariaKabath, PetrKnudstrup, EmilKorth, JudithLi, JieLuque, RafaelMathur, SavitaMontañes Rodríguez, PilarNarita, NorioNespral, DavidNiraula, PrajwalNowak, GrzegorzPalle, EnricPätzold, MartinPrieto-Arranz, JorgeRauer, HeikeRedfield, SethRibas, IgnasiSkarka, MarekSmith, Alexis M. S.Rowden, PamelaTorres, GuillermoVan Eylen, VincentVezie, Michael L.DOI: info:10.3847/2041-8213/ab17d9v. 876L24
Gandolfi, Davide, Fossati, Luca, Livingston, John H., Stassun, Keivan G., Grziwa, Sascha, Barragán, Oscar, Fridlund, Malcolm, Kubyshkina, Daria, Persson, Carina M., Dai, Fei, Lam, Kristine W. F., Albrecht, Simon, Batalha, Natalie, Beck, Paul G., Justesen, Anders Bo, Cabrera, Juan, Cartwright, Scott, Cochran, William D., Csizmadia, Szilard, Davies, Misty D., Deeg, Hans J., Eigmüller, Philipp, Endl, Michael, Erikson, Anders, Esposito, Massimiliano et al. 2019. "The Transiting Multi-planet System HD15337: Two Nearly Equal-mass Planets Straddling the Radius Gap." Astrophysical Journal Letters 876:L24.
ID: 151864
Type: article
Authors: Gandolfi, Davide; Fossati, Luca; Livingston, John H.; Stassun, Keivan G.; Grziwa, Sascha; Barragán, Oscar; Fridlund, Malcolm; Kubyshkina, Daria; Persson, Carina M.; Dai, Fei; Lam, Kristine W. F.; Albrecht, Simon; Batalha, Natalie; Beck, Paul G.; Justesen, Anders Bo; Cabrera, Juan; Cartwright, Scott; Cochran, William D.; Csizmadia, Szilard; Davies, Misty D.; Deeg, Hans J.; Eigmüller, Philipp; Endl, Michael; Erikson, Anders; Esposito, Massimiliano; García, Rafael A.; Goeke, Robert; González-Cuesta, Lucía; Guenther, Eike W.; Hatzes, Artie P.; Hidalgo, Diego; Hirano, Teruyuki; Hjorth, Maria; Kabath, Petr; Knudstrup, Emil; Korth, Judith; Li, Jie; Luque, Rafael; Mathur, Savita; Montañes Rodríguez, Pilar; Narita, Norio; Nespral, David; Niraula, Prajwal; Nowak, Grzegorz; Palle, Enric; Pätzold, Martin; Prieto-Arranz, Jorge; Rauer, Heike; Redfield, Seth; Ribas, Ignasi; Skarka, Marek; Smith, Alexis M. S.; Rowden, Pamela; Torres, Guillermo; Van Eylen, Vincent; Vezie, Michael L.
Abstract: We report the discovery of a super-Earth and a sub-Neptune transiting observed by the Transiting Exoplanet Survey Satellite (TESS) in Sectors 3 and 4. We combine the TESS photometry with archival High Accuracy Radial velocity Planet Searcher spectra to confirm the planetary nature of the transit signals and derive the masses of the two transiting planets. With an orbital period of 4.8 days, a mass of {7.51}-1.01+1.09 {M}\oplus and a radius of 1.64 ± 0.06 R , HD 15337 b joins the growing group of short-period super-Earths known to have a rocky terrestrial composition. The sub-Neptune HD 15337 c has an orbital period of 17.2 days, a mass of {8.11}-1.69+1.82 {{{M}}}\oplus , and a radius of 2.39 ± 0.12 R , suggesting that the planet might be surrounded by a thick atmospheric envelope. The two planets have similar masses and lie on opposite sides of the radius gap, and are thus an excellent testbed for planet formation and evolution theories. Assuming that HD 15337 c hosts a hydrogen-dominated envelope, we employ a recently developed planet atmospheric evolution algorithm in a Bayesian framework to estimate the history of the high-energy (extreme ultraviolet and X-ray) emission of the host star. We find that at an age of 150 Myr, the star possessed on average between 3.7 and 127 times the high-energy luminosity of the current Sun.
Absolute dimensions of the low-mass eclipsing binary system NSVS 10653195Iglesias-Marzoa, RamónArévalo, María J.López-Morales, MercedesTorres, GuillermoLázaro, CarlosCoughlin, Jeffrey L.DOI: info:10.1051/0004-6361/201935516v. 627A153
Iglesias-Marzoa, Ramón, Arévalo, María J., López-Morales, Mercedes, Torres, Guillermo, Lázaro, Carlos, and Coughlin, Jeffrey L. 2019. "Absolute dimensions of the low-mass eclipsing binary system NSVS 10653195." Astronomy and Astrophysics 627:A153.
ID: 154158
Type: article
Authors: Iglesias-Marzoa, Ramón; Arévalo, María J.; López-Morales, Mercedes; Torres, Guillermo; Lázaro, Carlos; Coughlin, Jeffrey L.
Abstract: Context. Low-mass stars in eclipsing binary systems show radii larger and effective temperatures lower than theoretical stellar models predict for isolated stars with the same masses. Eclipsing binaries with low- mass components are hard to find due to their low luminosity. As a consequence, the analysis of the known low-mass eclipsing systems is key to understand this behavior. Aims: We aim to investigate the mass-radius relation for low-mass stars and the cause of the deviation of the observed radii in low-mass detached eclipsing binary stars (LMDEB) from theoretical stellar models. Methods: We developed a physical model of the LMDEB system NSVS 10653195 to accurately measure the masses and radii of the components. We obtained several high- resolution spectra in order to fit a spectroscopic orbit. Standardized absolute photometry was obtained to measure reliable color indices and to measure the mean Teff of the system in out-of-eclipse phases. We observed and analyzed optical VRI and infrared JK band differential light-curves which were fitted using PHOEBE. A Markov chain Monte-Carlo (MCMC) simulation near the solution found provides robust uncertainties for the fitted parameters. Results: NSVS 10653195 is a detached eclipsing binary composed of two similar stars with masses of M1 = 0.6402 ± 0.0052 M and M2 = 0.6511 ± 0.0052 M and radii of R1 = 0.687+0.017-0.024 R and R2 = 0.672+0.018-0.022 R. Spectral types were estimated to be K6V and K7V. These stars rotate in a circular orbit with an orbital inclination of i = 86.22 ± 0.61 degrees and a period of P = 0.5607222(2) d. The distance to the system is estimated to be d = 135.2+7.6-7.9 pc, in excellent agreement with the value from Gaia. If solar metallicity were assumed, the age of the system would be older than log (age) ̃ 8 based on the Mbol-log Teff diagram. Conclusions: NSVS 10653195 is composed of two oversized and active K stars. While their radii is above model predictions their Teff are in better agreement with models. Full Tables 1-3 and 7 are only available at the CDS via anonymous ftp to ( or via bin/qcat?J/A+A/627/A153