Publication Search Results

ID: 159268
Type: article
Authors: Addison, Brett C.; Wright, Duncan J.; Nicholson, Belinda A.; Cale, Bryson; Mocnik, Teo; Huber, Daniel; Plavchan, Peter; Wittenmyer, Robert A.; Vanderburg, Andrew; Chaplin, William J.; Chontos, Ashley; Clark, Jake T.; Eastman, Jason D.; Ziegler, Carl; Brahm, Rafael; Carter, Bradley D.; Clerte, Mathieu; Espinoza, Néstor; Horner, Jonathan; Bentley, John; Jordán, Andrés; Kane, Stephen R.; Kielkopf, John F.; Laychock, Emilie; Mengel, Matthew W.; Okumura, Jack; Stassun, Keivan G.; Bedding, Timothy R.; Bowler, Brendan P.; Burnelis, Andrius; Blanco-Cuaresma, Sergi; Collins, Michaela; Crossfield, Ian; Davis, Allen B.; Evensberget, Dag; Heitzmann, Alexis; Howell, Steve B.; Law, Nicholas; Mann, Andrew W.; Marsden, Stephen C.; Matson, Rachel A.; O'Connor, James H.; Shporer, Avi; Stevens, Catherine; Tinney, C. G.; Tylor, Christopher; Wang, Songhu; Zhang, Hui; Henning, Thomas; Kossakowski, Diana; Ricker, George; Sarkis, Paula; Schlecker, Martin; Torres, Pascal; Vanderspek, Roland; Latham, David W.; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Mireles, Ismael; Rowden, Pam; Pepper, Joshua; Daylan, Tansu; Schlieder, Joshua E.; Collins, Karen A.; Collins, Kevin I.; Tan, Thiam-Guan; Ball, Warrick H.; Basu, Sarbani; Buzasi, Derek L.; Campante, Tiago L.; Corsaro, Enrico; González-Cuesta, L.; Davies, Guy R.; de Almeida, Leandro; Do Nascimento, Jose-Dias, Jr.; García, Rafael A.; Guo, Zhao; Handberg, Rasmus; Hekker, Saskia; Hey, Daniel R.; Kallinger, Thomas; Kawaler, Steven D.; Kayhan, Cenk; Kuszlewicz, James S.; Lund, Mikkel N.; Lyttle, Alexander; Mathur, Savita; Miglio, Andrea; Mosser, Benoit; Nielsen, Martin B.; Serenelli, Aldo M.; Aguirre, Victor Silva; Themeßl, Nathalie
Abstract: We report the discovery of a warm sub-Saturn, TOI-257b (HD 19916b), based on data from NASA's Transiting Exoplanet Survey Satellite (TESS). The transit signal was detected by TESS and confirmed to be of planetary origin based on radial velocity observations. An analysis of the TESS photometry, the MINERVA-Australis, FEROS, and HARPS radial velocities, and the asteroseismic data of the stellar oscillations reveals that TOI-257b has a mass of M_P = 0.138 ± 0.023 $\rm {M_J}$ (43.9 ± 7.3 $\, M_{\rm \oplus}$ ), a radius of R_P = 0.639 ± 0.013 $\rm {R_J}$ (7.16 ± 0.15 $\, \mathrm{ R}_{\rm \oplus}$ ), bulk density of $0.65^{+0.12}_{-0.11}$ (cgs), and period $18.38818^{+0.00085}_{-0.00084}$ $\rm {days}$ . TOI-257b orbits a bright (V = 7.612 mag) somewhat evolved late F-type star with M_* = 1.390 ± 0.046 $\rm {M_{sun}}$ , R_* = 1.888 ± 0.033 $\rm {R_{sun}}$ , T_eff = 6075 ± 90 $\rm {K}$ , and vsin i = 11.3 ± 0.5 km s^-1. Additionally, we find hints for a second non-transiting sub-Saturn mass planet on a ∼71 day orbit using the radial velocity data. This system joins the ranks of a small number of exoplanet host stars (∼100) that have been characterized with asteroseismology. Warm sub-Saturns are rare in the known sample of exoplanets, and thus the discovery of TOI-257b is important in the context of future work studying the formation and migration history of similar planetary systems.

ID: 159333
Type: article
Authors: Carmichael, Theron W.; Quinn, Samuel N.; Zhou, George; Grieves, Nolan; Irwin, Jonathan M.; Stassun, Keivan G.; Vanderburg, Andrew M.; Winn, Joshua N.; Bouchy, Francois; Brasseur, Clara E.; Briceño, César; Caldwell, Douglas A.; Charbonneau, David; Collins, Karen A.; Colon, Knicole D.; Eastman, Jason D.; Fausnaugh, Michael; Fong, William; Fűrész, Gábor; Huang, Chelsea; Jenkins, Jon M.; Kielkopf, John F.; Latham, David W.; Law, Nicholas; Lund, Michael B.; Mann, Andrew W.; Ricker, George R.; Rodriguez, Joseph E.; Schwarz, Richard P.; Shporer, Avi; Tenenbaum, Peter; Wood, Mackenna L.; Ziegler, Carl
Abstract: We report the discovery of two transiting brown dwarfs (BDs), TOI-811b and TOI-852b, from NASA's Transiting Exoplanet Survey Satellite mission. These two transiting BDs have similar masses but very different radii and ages. Their host stars have similar masses, effective temperatures, and metallicities. The younger and larger transiting BD is TOI-811b at a mass of M_b = 59.9 ± 13.0M_J and radius of R_b = 1.26 ± 0.06R_J, and it orbits its host star in a period of P = 25.16551 ± 0.00004 days. We derive the host star's age of ${93}_{-29}^{+61}$ Myr from an application of gyrochronology. The youth of this system, rather than external heating from its host star, is why this BD's radius is relatively large. This constraint on the youth of TOI-811b allows us to test substellar mass-radius evolutionary models at young ages where the radius of BDs changes rapidly. TOI-852b has a similar mass at M_b = 53.7 ± 1.4M_J but is much older (4 or 8 Gyr, based on bimodal isochrone results of the host star) and is also smaller with a radius of R_b = 0.83 ± 0.04R_J. TOI-852b's orbital period is P = 4.94561 ± 0.00008 days. TOI-852b joins the likes of other old transiting BDs that trace out the oldest substellar mass-radius evolutionary models where contraction of the BD's radius slows and approaches a constant value. Both host stars have a mass of M_⋆ = 1.32M_⊙ ± 0.05 and differ in their radii, T_eff, and [Fe/H], with TOI-811 having R_⋆ = 1.27 ± 0.09R_⊙, T_eff = 6107 ± 77 K, and [Fe/H] = + 0.40 ± 0.09 and TOI-852 having R_⋆ = 1.71 ± 0.04R_⊙, T_eff = 5768 ± 84 K, and [Fe/H] = + 0.33 ± 0.09. We take this opportunity to examine how TOI-811b and TOI-852b serve as test points for young and old substellar isochrones, respectively.

ID: 159325
Type: article
Authors: Dalba, Paul A.; Kane, Stephen R.; Isaacson, Howard; Giacalone, Steven; Howard, Andrew W.; Rodriguez, Joseph E.; Vanderburg, Andrew; Eastman, Jason D.; Kraus, Adam L.; Dupuy, Trent J.; Weiss, Lauren M.; Schwieterman, Edward W.
Abstract: Despite the severe bias of the transit method of exoplanet discovery toward short orbital periods, a modest sample of transiting exoplanets with orbital periods greater than 100 days is known. Long-term radial velocity (RV) surveys are pivotal to confirming these signals and generating a set of planetary masses and densities for planets receiving moderate to low irradiation from their host stars. Here we conduct RV observations of Kepler-1514 from the Keck I telescope using the High Resolution Echelle Spectrometer. From these data, we measure the mass of the statistically validated giant (1.108 ± 0.023 R_J) exoplanet Kepler-1514 b with a 218-day orbital period as 5.28 ± 0.22 M_J. The bulk density of this cool (∼390 K) giant planet is ${4.82}_{-0.25}^{+0.26}$ g cm^-3, consistent with a core supported by electron degeneracy pressure. We also infer an orbital eccentricity of ${0.401}_{-0.014}^{+0.013}$ from the RV and transit observations, which is consistent with planet-planet scattering and disk cavity migration models. The Kepler-1514 system contains an Earth-size, Kepler Object of Interest on a 10.5-day orbit that we statistically validate against false-positive scenarios, including those involving a neighboring star. The combination of the brightness (V = 11.8) of the host star and the long period, low irradiation, and high density of Kepler-1514 b places this system among a rare group of known exoplanetary systems and as one that is amenable to continued study. ^* Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

ID: 159319
Type: article
Authors: Dawson, Rebekah I.; Huang, Chelsea X.; Brahm, Rafael; Collins, Karen A.; Hobson, Melissa J.; Jordán, Andrés; Dong, Jiayin; Korth, Judith; Trifonov, Trifon; Abe, Lyu; Agabi, Abdelkrim; Bruni, Ivan; Butler, R. Paul; Barbieri, Mauro; Collins, Kevin I.; Conti, Dennis M.; Crane, Jeffrey D.; Crouzet, Nicolas; Dransfield, Georgina; Evans, Phil; Espinoza, Néstor; Gan, Tianjun; Guillot, Tristan; Henning, Thomas; Lissauer, Jack J.; Jensen, Eric L. N.; Sainte, Wenceslas Marie; Mékarnia, Djamel; Myers, Gordon; Nandakumar, Sangeetha; Relles, Howard M.; Sarkis, Paula; Torres, Pascal; Shectman, Stephen; Schmider, François-Xavier; Shporer, Avi; Stockdale, Chris; Teske, Johanna; Triaud, Amaury H. M. J.; Wang, Sharon Xuesong; Ziegler, Carl; Ricker, G.; Vanderspek, R.; Latham, David W.; Seager, S.; Winn, J.; Jenkins, Jon M.; Bouma, L. G.; Burt, Jennifer A.; Charbonneau, David; Levine, Alan M.; McDermott, Scott; McLean, Brian; Rose, Mark E.; Vanderburg, Andrew; Wohler, Bill
Abstract: TOI-216 hosts a pair of warm, large exoplanets discovered by the TESS mission. These planets were found to be in or near the 2:1 resonance, and both of them exhibit transit timing variations (TTVs). Precise characterization of the planets' masses and radii, orbital properties, and resonant behavior can test theories for the origins of planets orbiting close to their stars. Previous characterization of the system using the first six sectors of TESS data suffered from a degeneracy between planet mass and orbital eccentricity. Radial-velocity measurements using HARPS, FEROS, and the Planet Finder Spectrograph break that degeneracy, and an expanded TTV baseline from TESS and an ongoing ground-based transit observing campaign increase the precision of the mass and eccentricity measurements. We determine that TOI-216c is a warm Jupiter, TOI-216b is an eccentric warm Neptune, and that they librate in 2:1 resonance with a moderate libration amplitude of ${60}_{-2}^{+2}$ deg, a small but significant free eccentricity of ${0.0222}_{-0.0003}^{+0.0005}$ for TOI-216b, and a small but significant mutual inclination of 1°2-3°9 (95% confidence interval). The libration amplitude, free eccentricity, and mutual inclination imply a disturbance of TOI-216b before or after resonance capture, perhaps by an undetected third planet.

ID: 159336
Type: article
Authors: Daylan, Tansu; Pinglé, Kartik; Wright, Jasmine; Günther, Maximilian N.; Stassun, Keivan G.; Kane, Stephen R.; Vanderburg, Andrew; Jontof-Hutter, Daniel; Rodriguez, Joseph E.; Shporer, Avi; Huang, Chelsea X.; Mikal-Evans, Thomas; Badenas-Agusti, Mariona; Collins, Karen A.; Rackham, Benjamin V.; Quinn, Samuel N.; Cloutier, Ryan; Collins, Kevin I.; Guerra, Pere; Jensen, Eric L. N.; Kielkopf, John F.; Massey, Bob; Schwarz, Richard P.; Charbonneau, David; Lissauer, Jack J.; Irwin, Jonathan M.; Baştürk, Özgür; Fulton, Benjamin; Soubkiou, Abderahmane; Zouhair, Benkhaldoun; Howell, Steve B.; Ziegler, Carl; Briceño, César; Law, Nicholas; Mann, Andrew W.; Scott, Nic; Furlan, Elise; Ciardi, David R.; Matson, Rachel; Hellier, Coel; Anderson, David R.; Butler, R. Paul; Crane, Jeffrey D.; Teske, Johanna K.; Shectman, Stephen A.; Kristiansen, Martti H.; Terentev, Ivan A.; Schwengeler, Hans Martin; Ricker, George R.; Vanderspek, Roland; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Berta-Thompson, Zachory K.; Bouma, Luke G.; Fong, William; Furesz, Gabor; Henze, Christopher E.; Morgan, Edward H.; Quintana, Elisa; Ting, Eric B.; Twicken, Joseph D.
Abstract: We report the discovery and validation of four extrasolar planets hosted by the nearby, bright, Sun-like (G3V) star HD 108236 using data from the Transiting Exoplanet Survey Satellite (TESS). We present transit photometry, reconnaissance, and precise Doppler spectroscopy, as well as high-resolution imaging, to validate the planetary nature of the objects transiting HD 108236, also known as the TESS Object of Interest (TOI) 1233. The innermost planet is a possibly rocky super-Earth with a period of ${3.79523}_{-0.00044}^{+0.00047}$ days and has a radius of 1.586 ± 0.098 R_⊕. The outer planets are sub-Neptunes, with potential gaseous envelopes, having radii of ${2.068}_{-0.091}^{+0.10}$ R_⊕, 2.72 ± 0.11 R_⊕, and ${3.12}_{-0.12}^{+0.13}$ R_⊕ and periods of ${6.20370}_{-0.00052}^{+0.00064}$ days, ${14.17555}_{-0.0011}^{+0.00099}$ days, and ${19.5917}_{-0.0020}^{+0.0022}$ days, respectively. With V and K_s magnitudes of 9.2 and 7.6, respectively, the bright host star makes the transiting planets favorable targets for mass measurements and, potentially, for atmospheric characterization via transmission spectroscopy. HD 108236 is the brightest Sun-like star in the visual (V) band known to host four or more transiting exoplanets. The discovered planets span a broad range of planetary radii and equilibrium temperatures and share a common history of insolation from a Sun-like star (R_⋆ = 0.888 ± 0.017 R_⊙, T_eff = 5730 ± 50 K), making HD 108236 an exciting, opportune cosmic laboratory for testing models of planet formation and evolution.

ID: 159324
Type: article
Authors: Hurt, Spencer A.; Quinn, Samuel N.; Latham, David W.; Vanderburg, Andrew; Esquerdo, Gilbert A.; Calkins, Michael L.; Berlind, Perry; Angus, Ruth; Latham, Christian A.; Zhou, George
Abstract: We present an analysis of 1524 spectra of Vega spanning 10 yr, in which we search for periodic radial-velocity variations. A signal with a periodicity of 0.676 day and a semi-amplitude of ∼10 m s^-1 is consistent with the rotation period measured over much shorter time spans by previous spectroscopic and spectropolarimetric studies, confirming the presence of surface features on this A0 star. The activity signal appears to evolve on long timescales, which may indicate the presence of failed fossil magnetic fields on Vega. TESS data reveal Vega's photometric rotational modulation for the first time, with a total amplitude of only 10 ppm. A comparison of the spectroscopic and photometric amplitudes suggests that the surface features may be dominated by bright plages rather than dark spots. For the shortest orbital periods, transit and radial-velocity injection recovery tests exclude the presence of transiting planets larger than 2 R_⊕ and most non-transiting giant planets. At long periods, we combine our radial velocities with direct imaging from the literature to produce detection limits for Vegan planets and brown dwarfs out to distances of 15 au. Finally, we detect a candidate radial-velocity signal with a period of 2.43 days and a semi-amplitude of 6 m s^-1. If caused by an orbiting companion, its minimum mass would be ∼20 M_⊕; because of Vega's pole-on orientation, this would correspond to a Jovian planet if the orbit is aligned with the stellar spin. We discuss the prospects for confirmation of this candidate planet.

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 T_eff. 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.

ID: 159316
Type: article
Authors: Rodriguez, Joseph E.; Quinn, Samuel N.; Zhou, George; Vanderburg, Andrew; Nielsen, Louise D.; Wittenmyer, Robert A.; Brahm, Rafael; Reed, Phillip A.; Huang, Chelsea X.; Vach, Sydney; Ciardi, David R.; Oelkers, Ryan J.; Stassun, Keivan G.; Hellier, Coel; Gaudi, B. Scott; Eastman, Jason D.; Collins, Karen A.; Bieryla, Allyson; Christian, Sam; Latham, David W.; Carleo, Ilaria; Wright, Duncan J.; Matthews, Elisabeth; Gonzales, Erica J.; Ziegler, Carl; Dressing, Courtney D.; Howell, Steve B.; Tan, Thiam-Guan; Wittrock, Justin; Plavchan, Peter; McLeod, Kim K.; Baker, David; Wang, Gavin; Radford, Don J.; Schwarz, Richard P.; Esposito, Massimiliano; Ricker, George R.; Vanderspek, Roland K.; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Addison, Brett; Anderson, D. R.; Barclay, Thomas; Beatty, Thomas G.; Berlind, Perry; Bouchy, Francois; Bowen, Michael; Bowler, Brendan P.; Brasseur, C. E.; Briceño, César; Caldwell, Douglas A.; Calkins, Michael L.; Cartwright, Scott; Chaturvedi, Priyanka; Chaverot, Guillaume; Chimaladinne, Sudhish; Christiansen, Jessie L.; Collins, Kevin I.; Crossfield, Ian J. M.; Eastridge, Kevin; Espinoza, Néstor; Esquerdo, Gilbert A.; Feliz, Dax L.; Fenske, Tyler; Fong, William; Gan, Tianjun; Giacalone, Steven; Gill, Holden; Gordon, Lindsey; Granados, A.; Grieves, Nolan; Guenther, Eike W.; Guerrero, Natalia; Henning, Thomas; Henze, Christopher E.; Hesse, Katharine; Hobson, Melissa J.; Horner, Jonathan; James, David J.; Jensen, Eric L. N.; Jimenez, Mary; Jordán, Andrés; Kane, Stephen R.; Kielkopf, John; Kim, Kingsley; Kuhn, Rudolf B.; Latouf, Natasha; Law, Nicholas M.; Levine, Alan M.; Lund, Michael B.; Mann, Andrew W.; Mao, Shude; Matson, Rachel A.; Mengel, Matthew W.; Mink, Jessica; Newman, Patrick; O'Dwyer, Tanner; Okumura, Jack; Palle, Enric; Pepper, Joshua; Quintana, Elisa V.; Sarkis, Paula; Savel, Arjun B.; Schlieder, Joshua E.; Schnaible, Chloe; Shporer, Avi; Sefako, Ramotholo; Seidel, Julia V.; Siverd, Robert J.; Skinner, Brett; Stalport, Manu; Stevens, Daniel J.; Stibbards, Caitlin; Tinney, C. G.; West, R. G.; Yahalomi, Daniel A.; Zhang, Hui
Abstract: We present the discovery and characterization of five hot and warm Jupiters-TOI-628 b (TIC 281408474; HD 288842), TOI-640 b (TIC 147977348), TOI-1333 b (TIC 395171208, BD+47 3521A), TOI-1478 b (TIC 409794137), and TOI-1601 b (TIC 139375960)-based on data from NASA's Transiting Exoplanet Survey Satellite (TESS). The five planets were identified from the full-frame images and were confirmed through a series of photometric and spectroscopic follow-up observations by the TESS Follow-up Observing Program Working Group. The planets are all Jovian size (R_P = 1.01-1.77 R_J) and have masses that range from 0.85 to 6.33 M_J. The host stars of these systems have F and G spectral types (5595 ≤ T_eff ≤ 6460 K) and are all relatively bright (9.5 ≤ 6460 K) and are all relatively bright (9.5 ≤ 6460 K) and are all relatively bright (9.5 ≤ 6460 K) and are all relatively bright (9.5 ≤ 6460 K) and are all relatively bright (9.5 ≤ 6460 K) and are all relatively bright (9.5 _P > 1.7 R_J, possibly a result of its host star's evolution) and resides on an orbit with a period longer than 5 days. TOI-628 b is the most massive, hot Jupiter discovered to date by TESS with a measured mass of ${6.31}_{-0.30}^{+0.28}$ M_J and a statistically significant, nonzero orbital eccentricity of e = ${0.074}_{-0.022}^{+0.021}$ . This planet would not have had enough time to circularize through tidal forces from our analysis, suggesting that it might be remnant eccentricity from its migration. The longest-period planet in this sample, TOI-1478 b (P = 10.18 days), is a warm Jupiter in a circular orbit around a near-solar analog. NASA's TESS mission is continuing to increase the sample of well-characterized hot and warm Jupiters, complementing its primary mission goals.

ID: 159327
Type: article
Authors: Seager, Sara; Knapp, Mary; Demory, Brice-Olivier; Krishnamurthy, Akshata; Huang, Chelsea X.; Agusti, Mariona Badenas; Shporer, Avi; Weisserman, Drew; Becker, Juliette; Vanderburg, Andrew; Smith, Matthew; Pong, Christopher M.; Bailey, Vanessa P.; Donner, Amanda; Di Pasquale, Peter; Campuzano, Brian; Smith, Colin; Luu, Jason; Babuscia, Alessandra; Bocchino, Robert L., Jr.; Loveland, Jessica; Colley, Cody; Gedenk, Tobias; Kulkarni, Tejas; Hughes, Kyle; White, Mary; Krajewski, Joel; Fesq, Lorraine; Ricker, George; Vanderspek, Roland; Latham, David W.; Jenkins, Jon M.; Winn, Joshua N.; Caldwell, Douglas A.; Collins, Karen A.; Dragomir, Diana; Fausnaugh, Michael; Glidden, Ana; Schlieder, Joshua E.; Twicken, Joseph D.; Wohler, Bill
Abstract: HD 219134 is a K3V dwarf star with six reported radial-velocity discovered planets. The two innermost planets b and c show transits, raising the possibility of this system to be the nearest (6.53 pc), brightest (V = 5.57) example of a star with a compact multiple transiting planet system. Ground-based searches for transits of planets beyond b and c are not feasible because of the infrequent transits, long transit duration (∼5 hr), shallow transit depths (_⊕. We provide TESS updated transit times and periods for HD 219134 b and c, which are designated TOI 1469.01 and 1469.02 respectively.

ID: 159334
Type: article
Authors: Sha, Lizhou; Huang, Chelsea X.; Shporer, Avi; Rodriguez, Joseph E.; Vanderburg, Andrew; Brahm, Rafael; Hagelberg, Janis; Matthews, Elisabeth C.; Ziegler, Carl; Livingston, John H.; Stassun, Keivan G.; Wright, Duncan J.; Crane, Jeffrey D.; Espinoza, Néstor; Bouchy, François; Bakos, Gáspár Á.; Collins, Karen A.; Zhou, George; Bieryla, Allyson; Hartman, Joel D.; Wittenmyer, Robert A.; Nielsen, Louise D.; Plavchan, Peter; Bayliss, Daniel; Sarkis, Paula; Tan, Thiam-Guan; Cloutier, Ryan; Mancini, Luigi; Jordán, Andrés; Wang, Sharon; Henning, Thomas; Narita, Norio; Penev, Kaloyan; Teske, Johanna K.; Kane, Stephen R.; Mann, Andrew W.; Addison, Brett C.; Tamura, Motohide; Horner, Jonathan; Barbieri, Mauro; Burt, Jennifer A.; Díaz, Matías R.; Crossfield, Ian J. M.; Dragomir, Diana; Drass, Holger; Feinstein, Adina D.; Zhang, Hui; Hart, Rhodes; Kielkopf, John F.; Jensen, Eric L. N.; Montet, Benjamin T.; Ottoni, Gaël; Schwarz, Richard P.; Rojas, Felipe; Nespral, David; Torres, Pascal; Mengel, Matthew W.; Udry, Stéphane; Zapata, Abner; Snoddy, Erin; Okumura, Jack; Ricker, George R.; Vanderspek, Roland K.; Latham, David W.; Winn, Joshua N.; Seager, Sara; Jenkins, Jon M.; Colón, Knicole D.; Henze, Christopher E.; Krishnamurthy, Akshata; Ting, Eric B.; Vezie, Michael; Villanueva, Steven
Abstract: We report the discovery of two short-period Saturn-mass planets, one transiting the G subgiant TOI-954 (TIC 44792534, V = 10.343, T = 9.78) observed in TESS sectors 4 and 5 and one transiting the G dwarf K2-329 (EPIC 246193072, V = 12.70, K = 10.67) observed in K2 campaigns 12 and 19. We confirm and characterize these two planets with a variety of ground-based archival and follow-up observations, including photometry, reconnaissance spectroscopy, precise radial velocity, and high-resolution imaging. Combining all available data, we find that TOI-954 b has a radius of ${0.852}_{-0.062}^{+0.053}\,{R}_{{\rm{J}}}$ and a mass of ${0.174}_{-0.017}^{+0.018}$ M_J and is in a 3.68 day orbit, while K2-329 b has a radius of ${0.774}_{-0.024}^{+0.026}\,{R}_{{\rm{J}}}$ and a mass of ${0.260}_{-0.022}^{+0.020}$ M_J and is in a 12.46 day orbit. As TOI-954 b is 30 times more irradiated than K2-329 b but more or less the same size, these two planets provide an opportunity to test whether irradiation leads to inflation of Saturn-mass planets and contribute to future comparative studies that explore Saturn-mass planets at contrasting points in their lifetimes.

ID: 159320
Type: article
Authors: Tofflemire, Benjamin M.; Rizzuto, Aaron C.; Newton, Elisabeth R.; Kraus, Adam L.; Mann, Andrew W.; Vanderburg, Andrew; Nelson, Tyler; Hawkins, Keith; Wood, Mackenna L.; Zhou, George; Quinn, Samuel N.; Howell, Steve B.; Collins, Karen A.; Schwarz, Richard P.; Stassun, Keivan G.; Bouma, Luke G.; Essack, Zahra; Osborn, Hugh; Boyd, Patricia T.; Fűrész, Gábor; Glidden, Ana; Twicken, Joseph D.; Wohler, Bill; McLean, Brian; Ricker, George R.; Vanderspek, Roland; Latham, David W.; Seager, S.; Winn, Joshua N.; Jenkins, Jon M.
Abstract: The detection and characterization of young planetary systems offer a direct path to study the processes that shape planet evolution. We report on the discovery of a sub-Neptune-sized planet orbiting the young star HD 110082 (TOI-1098). Transit events we initially detected during TESS Cycle 1 are validated with time-series photometry from Spitzer. High-contrast imaging and high-resolution, optical spectra are also obtained to characterize the stellar host and confirm the planetary nature of the transits. The host star is a late-F dwarf (M_⋆ = 1.2M_⊙) with a low-mass, M dwarf binary companion (M_⋆ = 0.26M_⊙) separated by nearly one arcminute (∼6200 au). Based on its rapid rotation and Lithium absorption, HD 110082 is young, but is not a member of any known group of young stars (despite proximity to the Octans association). To measure the age of the system, we search for coeval, phase-space neighbors and compile a sample of candidate siblings to compare with the empirical sequences of young clusters and to apply quantitative age-dating techniques. In doing so, we find that HD 110082 resides in a new young stellar association we designate MELANGE-1, with an age of ${250}_{-70}^{+50}$ Myr. Jointly modeling the TESS and Spitzer light curves, we measure a planetary orbital period of 10.1827 days and radius of R_p = 3.2 ± 0.1R_⊕. HD 110082 b's radius falls in the largest 12% of field-age systems with similar host-star mass and orbital period. This finding supports previous studies indicating that young planets have larger radii than their field-age counterparts.

ID: 158027
Type: article
Authors: Badenas-Agusti, Mariona; Günther, Maximilian N.; Daylan, Tansu; Mikal-Evans, Thomas; Vanderburg, Andrew; Huang, Chelsea X.; Matthews, Elisabeth; Rackham, Benjamin V.; Bieryla, Allyson; Stassun, Keivan G.; Kane, Stephen R.; Shporer, Avi; Fulton, Benjamin J.; Hill, Michelle L.; Nowak, Grzegorz; Ribas, Ignasi; Pallé, Enric; Jenkins, Jon M.; Latham, David W.; Seager, Sara; Ricker, George R.; Vanderspek, Roland K.; Winn, Joshua N.; Abril-Pla, Oriol; Collins, Karen A.; Serra, Pere Guerra; Niraula, Prajwal; Rustamkulov, Zafar; Barclay, Thomas; Crossfield, Ian J. M.; Howell, Steve B.; Ciardi, David R.; Gonzales, Erica J.; Schlieder, Joshua E.; Caldwell, Douglas A.; Fausnaugh, Michael; McDermott, Scott; Paegert, Martin; Pepper, Joshua; Rose, Mark E.; Twicken, Joseph D.
Abstract: We present the discovery of three sub-Neptune-sized planets transiting the nearby and bright Sun-like star HD 191939 (TIC 269701147, TOI 1339), a K_s = 7.18 mag G8 V dwarf at a distance of only 54 pc. We validate the planetary nature of the transit signals by combining 5 months of data from the Transiting Exoplanet Survey Satellite with follow-up ground-based photometry, archival optical images, radial velocities, and high angular resolution observations. The three sub-Neptunes have similar radii ( ${R}_{{\rm{b}}}={3.42}_{-0.11}^{+0.11}$ , ${R}_{{\rm{c}}}={3.23}_{-0.11}^{+0.11}$ , and ${R}_{{\rm{d}}}={3.16}_{-0.11}^{+0.11}\,{R}_{\oplus }$ ), and their orbits are consistent with a stable, circular, and coplanar architecture near mean-motion resonances of 1:3 and 3:4 (P_b = 8.88, P_c = 28.58, and P_d = 38.35 days). The HD 191939 system is an excellent candidate for precise mass determinations of the planets with high-resolution spectroscopy due to the host star's brightness and low chromospheric activity. Moreover, the system's compact and near-resonant nature can provide an independent way to measure planetary masses via transit timing variations while also enabling dynamical and evolutionary studies. Finally, as a promising target for multiwavelength transmission spectroscopy of all three planets' atmospheres, HD 191939 can offer valuable insight into multiple sub-Neptunes born from a protoplanetary disk that may have resembled that of the early Sun.

ID: 157601
Type: article
Authors: Burt, Jennifer A.; Nielsen, Louise D.; Quinn, Samuel N.; Mamajek, Eric E.; Matthews, Elisabeth C.; Zhou, George; Seidel, Julia V.; Huang, Chelsea X.; Lopez, Eric; Soto, Maritza; Otegi, Jon; Stassun, Keivan G.; Kreidberg, Laura; Collins, Karen A.; Eastman, Jason D.; Rodriguez, Joseph E.; Vanderburg, Andrew; Halverson, Samuel P.; Teske, Johanna K.; Wang, Sharon X.; Butler, R. Paul; Bouchy, François; Dumusque, Xavier; Segransen, Damien; Shectman, Stephen A.; Crane, Jeffrey D.; Feng, Fabo; Montet, Benjamin T.; Feinstein, Adina D.; Beletski, Yuri; Flowers, Erin; Günther, Maximilian N.; Daylan, Tansu; Collins, Kevin I.; Conti, Dennis M.; Gan, Tianjun; Jensen, Eric L. N.; Kielkopf, John F.; Tan, Thiam-Guan; Helled, Ravit; Dorn, Caroline; Haldemann, Jonas; Lissauer, Jack J.; Ricker, George R.; Vanderspek, Roland; Latham, David W.; Seager, S.; Winn, Joshua N.; Jenkins, Jon M.; Twicken, Joseph D.; Smith, Jeffrey C.; Tenenbaum, Peter; Cartwright, Scott; Barclay, Thomas; Pepper, Joshua; Esquerdo, Gilbert; Fong, William
Abstract: We report the detection of a transiting hot Neptune exoplanet orbiting TOI-824 (SCR J1448-5735), a nearby (d = 64 pc) K4V star, using data from the Transiting Exoplanet Survey Satellite. The newly discovered planet has a radius R_p = 2.93 ± 0.20 ${R}_{\oplus }$ and an orbital period of 1.393 days. Radial velocity measurements using the Planet Finder Spectrograph and the High Accuracy Radial velocity Planet Searcher spectrograph confirm the existence of the planet, and we estimate its mass to be 18.47 ± 1.84 ${M}_{\oplus }$ . The planet's mean density is ${\rho }_{{\rm{p}}}$ = 4.03 ${}_{-0.78}^{+0.98}$ ${\rm{g}}\,{\mathrm{cm}}^{-3}$ , making it more than twice as dense as Neptune. TOI-824 b's high equilibrium temperature makes the planet likely to have a cloud-free atmosphere, and thus it is an excellent candidate for follow-up atmospheric studies. The detectability of TOI-824 b's atmosphere from both ground and space is promising and could lead to the detailed characterization of the most irradiated small planet at the edge of the hot Neptune desert that has retained its atmosphere to date.

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.

ID: 156961
Type: article
Authors: Dalba, Paul A.; Gupta, Arvind F.; Rodriguez, Joseph E.; Dragomir, Diana; Huang, Chelsea X.; Kane, Stephen R.; Quinn, Samuel N.; Bieryla, Allyson; Esquerdo, Gilbert A.; Fulton, Benjamin J.; Scarsdale, Nicholas; Batalha, Natalie M.; Beard, Corey; Behmard, Aida; Chontos, Ashley; Crossfield, Ian J. M.; Dressing, Courtney D.; Giacalone, Steven; Hill, Michelle L.; Hirsch, Lea A.; Howard, Andrew W.; Huber, Daniel; Isaacson, Howard; Kosiarek, Molly; Lubin, Jack; Mayo, Andrew W.; Mocnik, Teo; Akana Murphy, Joseph M.; Petigura, Erik A.; Robertson, Paul; Rosenthal, Lee J.; Roy, Arpita; Rubenzahl, Ryan A.; Van Zandt, Judah; Weiss, Lauren M.; Knudstrup, Emil; Andersen, Mads F.; Grundahl, Frank; Yao, Xinyu; Pepper, Joshua; Villanueva, Steven, Jr.; Ciardi, David R.; Cloutier, Ryan; Jacobs, Thomas Lee; Kristiansen, Martti H.; LaCourse, Daryll M.; Lendl, Monika; Osborn, Hugh P.; Palle, Enric; Stassun, Keivan G.; Stevens, Daniel J.; Ricker, George R.; Vanderspek, Roland; Latham, David W.; Seager, S.; Winn, Joshua N.; Jenkins, Jon M.; Caldwell, Douglas A.; Daylan, Tansu; Fong, William; Goeke, Robert F.; Rose, Mark E.; Rowden, Pamela; Schlieder, Joshua E.; Smith, Jeffrey C.; Vanderburg, Andrew
Abstract: We report the detection of a Saturn-size exoplanet orbiting HD 332231 (TOI 1456) in light curves from the Transiting Exoplanet Survey Satellite (TESS). HD 332231 -- an F8 dwarf star with a V-band magnitude of 8.56 -- was observed by TESS in Sectors 14 and 15. We detect a single-transit event in the Sector 15 presearch data conditioning (PDC) light curve. We obtain spectroscopic follow-up observations of HD 332231 with the Automated Planet Finder, Keck I, and SONG telescopes. The orbital period we infer from radial velocity (RV) observations leads to the discovery of another transit in Sector 14 that was masked by PDC due to scattered light contamination. A joint analysis of the transit and RV data confirms the planetary nature of HD 332231 b, a Saturn-size ( ${0.867}_{-0.025}^{+0.027}\ {R}_{{\rm{J}}} ), sub-Saturn-mass ( $0.244\pm 0.021\ {M}_{{\rm{J}}} ) exoplanet on a 18.71 day circular orbit. The low surface gravity of HD 332231 b and the relatively low stellar flux it receives make it a compelling target for transmission spectroscopy. Also, the stellar obliquity is likely measurable via the Rossiter-McLaughlin effect, an exciting prospect given the 0.14 au orbital separation of HD 332231 b. The spectroscopic observations do not provide substantial evidence for any additional planets in the HD 332231 system, but continued RV monitoring is needed to further characterize this system. We also predict that the frequency and duration of masked data in the PDC light curves for TESS Sectors 14-16 could hide transits of some exoplanets with orbital periods between 10.5 and 17.5 days.

ID: 157579
Type: article
Authors: Demory, B. -O; Pozuelos, F. J.; Gómez Maqueo Chew, Y.; Sabin, L.; Petrucci, R.; Schroffenegger, U.; Grimm, S. L.; Sestovic, M.; Gillon, M.; McCormac, J.; Barkaoui, K.; Benz, W.; Bieryla, Allyson; Bouchy, F.; Burdanov, A.; Collins, Karen A.; de Wit, J.; Dressing, C. D.; Garcia, L. J.; Giacalone, S.; Guerra, P.; Haldemann, J.; Heng, K.; Jehin, E.; Jofré, E.; Kane, S. R.; Lillo-Box, J.; Maigné, V.; Mordasini, C.; Morris, B. M.; Niraula, P.; Queloz, D.; Rackham, B. V.; Savel, A. B.; Soubkiou, A.; Srdoc, G.; Stassun, K. G.; Triaud, A. H. M. J.; Zambelli, R.; Ricker, G.; Latham, David W.; Seager, S.; Winn, J. N.; Jenkins, J. M.; Calvario-Velásquez, T.; Franco Herrera, J. A.; Colorado, E.; Cadena Zepeda, E. O.; Figueroa, L.; Watson, A. M.; Lugo-Ibarra, E. E.; Carigi, L.; Guisa, G.; Herrera, J.; Sierra Díaz, G.; Suárez, J. C.; Barrado, D.; Batalha, N. M.; Benkhaldoun, Z.; Chontos, A.; Dai, F.; Essack, Z.; Ghachoui, M.; Huang, C. X.; Huber, D.; Isaacson, H.; Lissauer, J. J.; Morales-Calderón, M.; Robertson, P.; Roy, A.; Twicken, J. D.; Vanderburg, A.; Weiss, L. M.
Abstract: We report the discovery and characterisation of a super-Earth and a sub-Neptune transiting the bright (K = 8.8), quiet, and nearby (37 pc) M3V dwarf TOI-1266. We validate the planetary nature of TOI-1266 b and c using four sectors of TESS photometry and data from the newly-commissioned 1-m SAINT-EX telescope located in San Pedro Mártir (México). We also include additional ground-based follow-up photometry as well as high-resolution spectroscopy and high-angular imaging observations. The inner, larger planet has a radius of R = 2.37_-0.12^+0.16 R_⊕ and an orbital period of 10.9 days. The outer, smaller planet has a radius of R = 1.56_-0.13^+0.15 R_⊕ on an 18.8-day orbit. The data are found to be consistent with circular, co-planar and stable orbits that are weakly influenced by the 2:1 mean motion resonance. Our TTV analysis of the combined dataset enables model-independent constraints on the masses and eccentricities of the planets. We find planetary masses of M_p = 13.5_-9.0^+11.0 M_⊕ ( (_⊕ at 2-σ) for TOI-1266 b and 2.2_-1.5^+2.0 M_⊕ ( (_⊕ at 2-σ) for TOI-1266 c. We find small but non-zero orbital eccentricities of 0.09_-0.05^+0.06 (<0.21 at 2-σ) for TOI-1266 b and 0.04 ± 0.03 (< 0.10 at 2-σ) for TOI-1266 c. The equilibrium temperatures of both planets are of 413 ± 20 and 344 ± 16 K, respectively, assuming a null Bond albedo and uniform heat redistribution from the day-side to the night-side hemisphere. The host brightness and negligible activity combined with the planetary system architecture and favourable planet-to-star radii ratios makes TOI-1266 an exquisite system for a detailed characterisation.

ID: 156340
Type: article
Authors: Díaz, Matías R.; Jenkins, James S.; Gandolfi, Davide; Lopez, Eric D.; Soto, Maritza G.; Cortés-Zuleta, Pía; Berdiñas, Zaira M.; Stassun, Keivan G.; Collins, Karen A.; Vines, José I.; Ziegler, Carl; Fridlund, Malcom; Jensen, Eric L. N.; Murgas, Felipe; Santerne, Alexandre; Wilson, Paul A.; Esposito, Massimiliano; Hatzes, Artie P.; Johnson, Marshall C.; Lam, Kristine W. F.; Livingston, John H.; Van Eylen, Vincent; Narita, Norio; Briceño, Cesar; Collins, Kevin I.; Csizmadia, Szilárd; Fausnaugh, Michael; Gan, Tianjun; García, Rafael A.; Georgieva, Iska; Glidden, Ana; González-Cuesta, Lucía; Jenkins, Jon M.; Latham, David W.; Law, Nicholas M.; Mann, Andrew W.; Mathur, Savita; Mireles, Ismael; Morris, Robert; Pallé, Enric; Persson, Carina M.; Ricker, George; Rinehart, Stephen; Rose, Mark E.; Seager, Sara; Smith, Jeffrey C.; Tan, Thiam-Guan; Tokovinin, Andrei; Vanderburg, Andrew; Vanderspek, Roland; Winn, Joshua N.; Yahalomi, Daniel A.
Abstract: The Neptune desert is a feature seen in the radius-period plane, whereby a notable dearth of short period, Neptune-like planets is found. Here, we report the Transiting Exoplanet Survey Satellite (TESS) discovery of a new short-period planet in the Neptune desert, orbiting the G-type dwarf TYC 8003-1117-1 (TOI-132). TESS photometry shows transit-like dips at the level of ∼1400 ppm occurring every ∼2.11 d. High-precision radial velocity follow-up with High Accuracy Radial Velocity Planet Searcher confirmed the planetary nature of the transit signal and provided a semi-amplitude radial velocity variation of 11.38 ^{+0.84}_{-0.85} m s^-1, which, when combined with the stellar mass of 0.97 ± 0.06 M_☉, provides a planetary mass of 22.40^{+1.90}_{-1.92} M_⊕. Modelling the TESS light curve returns a planet radius of 3.42^{+0.13}_{-0.14} R_⊕, and therefore the planet bulk density is found to be 3.08^{+0.44}_{-0.46} g cm^-3. Planet structure models suggest that the bulk of the planet mass is in the form of a rocky core, with an atmospheric mass fraction of 4.3^{+1.2}_{-2.3} per cent. TOI-132 b is a TESS Level 1 Science Requirement candidate, and therefore priority follow-up will allow the search for additional planets in the system, whilst helping to constrain low-mass planet formation and evolution models, particularly valuable for better understanding of the Neptune desert.

ID: 157807
Type: article
Authors: Fridlund, M.; Livingston, J.; Gandolfi, D.; Persson, C. M.; Lam, K. W. F.; Stassun, K. G.; Hellier, C.; Korth, J.; Hatzes, A. P.; Malavolta, L.; Luque, R.; Redfield, S.; Guenther, E. W.; Albrecht, S.; Barragan, O.; Benatti, S.; Bouma, L.; Cabrera, J.; Cochran, W. D.; Csizmadia, S.; Dai, F.; Deeg, H. J.; Esposito, M.; Georgieva, I.; Grziwa, S.; González Cuesta, L.; Hirano, T.; Jenkins, J. M.; Kabath, P.; Knudstrup, E.; Latham, David W.; Mathur, S.; Mullally, S. E.; Narita, N.; Nowak, G.; Olofsson, A. O. H.; Palle, E.; Pätzold, M.; Pompei, E.; Rauer, H.; Ricker, G.; Rodler, F.; Seager, S.; Serrano, L. M.; Smith, A. M. S.; Spina, L.; Subjak, J.; Tenenbaum, P.; Ting, E. B.; Vanderburg, A.; Vanderspek, R.; Van Eylen, V.; Villanueva, S.; Winn, J. N.
Abstract: We report the discovery of a planetary system orbiting TOI-763(aka CD-39 7945), a V = 10.2, high proper motion G-type dwarf star that was photometrically monitored by the TESS space mission in Sector 10. We obtain and model the stellar spectrum and find an object slightly smaller than the Sun, and somewhat older, but with a similar metallicity. Two planet candidates were found in the light curve to be transiting the star. Combining TESS transit photometry with HARPS high-precision radial velocity (RV) follow-up measurements confirm the planetary nature of these transit signals. We determine masses, radii, and bulk densities of these two planets. A third planet candidate was discovered serendipitously in the RV data. The inner transiting planet, TOI-763 b, has an orbital period of P_b = 5.6 d, a mass of M_b = 9.8 ± 0.8 M_⊕, and a radius of R_b = 2.37 ± 0.10 R_⊕. The second transiting planet, TOI-763 c, has an orbital period of P_c = 12.3 d, a mass of M_c = 9.3 ± 1.0 M_⊕, and a radius of R_c = 2.87 ± 0.11 R_⊕. We find the outermost planet candidate to orbit the star with a period of ∼48 d. If confirmed as a planet, it would have a minimum mass of M_d = 9.5 ± 1.6 M_⊕. We investigated the TESS light curve in order to search for a mono transit by planet d without success. We discuss the importance and implications of this planetary system in terms of the geometrical arrangements of planets orbiting G-type stars.

ID: 155671
Type: article
Authors: Frustagli, G.; Poretti, E.; Milbourne, Timothy; Malavolta, L.; Mortier, A.; Singh, V.; Bonomo, A. S.; Buchhave, L. A.; Zeng, L.; Vanderburg, Andrew; Udry, S.; Andreuzzi, G.; Collier-Cameron, A.; Cosentino, R.; Damasso, M.; Ghedina, A.; Harutyunyan, A.; Haywood, Raphaëlle D.; Latham, David W.; López-Morales, Mercedes; Lorenzi, V.; Martinez Fiorenzano, A. F.; Mayor, M.; Micela, G.; Molinari, E.; Pepe, F.; Phillips, David; Rice, K.; Sozzetti, A.
Abstract: Ultra-short period (USP) planets are a class of exoplanets with periods shorter than one day. The origin of this sub-population of planets is still unclear, with different formation scenarios highly dependent on the composition of the USP planets. A better understanding of this class of exoplanets will, therefore, require an increase in the sample of such planets that have accurate and precise masses and radii, which also includes estimates of the level of irradiation and information about possible companions. Here we report a detailed characterization of a USP planet around the solar-type star HD 80653 ≡EP 251279430 using the K2 light curve and 108 precise radial velocities obtained with the HARPS-N spectrograph, installed on the Telescopio Nazionale Galileo. From the K2 C16 data, we found one super-Earth planet (R_b = 1.613 ± 0.071 R_⊕) transiting the star on a short-period orbit (P_b = 0.719573 ± 0.000021 d). From our radial velocity measurements, we constrained the mass of HD 80653 b to M_b = 5.60 ± 0.43 M_⊕. We also detected a clear long-term trend in the radial velocity data. We derived the fundamental stellar parameters and determined a radius of R_⋆ = 1.22 ± 0.01 R_☉ and mass of M_⋆ = 1.18 ± 0.04 M_☉, suggesting that HD 80653 has an age of 2.7 ± 1.2 Gyr. The bulk density (ρ_b = 7.4 ± 1.1 g cm^-3) of the planet is consistent with an Earth-like composition of rock and iron with no thick atmosphere. Our analysis of the K2 photometry also suggests hints of a shallow secondary eclipse with a depth of 8.1 ± 3.7 ppm. Flux variations along the orbital phase are consistent with zero. The most important contribution might come from the day-side thermal emission from the surface of the planet at T ~ 3480 K. HARPS-N spectroscopic data 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/633/A133 Based on observations made with the Italian Telescopio Nazionale Galileo (TNG) operated by the Fundación Galileo Galilei (FGG) of the Istituto Nazionale di Astrofisica (INAF) at the Observatorio del Roque de los Muchachos (La Palma, Canary Islands, Spain).

ID: 157602
Type: article
Authors: Gilbert, Emily A.; Barclay, Thomas; Schlieder, Joshua E.; Quintana, Elisa V.; Hord, Benjamin J.; Kostov, Veselin B.; Lopez, Eric D.; Rowe, Jason F.; Hoffman, Kelsey; Walkowicz, Lucianne M.; Silverstein, Michele L.; Rodriguez, Joseph E.; Vanderburg, Andrew; Suissa, Gabrielle; Airapetian, Vladimir S.; Clement, Matthew S.; Raymond, Sean N.; Mann, Andrew W.; Kruse, Ethan; Lissauer, Jack J.; Colón, Knicole D.; Kopparapu, Ravi Kumar; Kreidberg, Laura; Zieba, Sebastian; Collins, Karen A.; Quinn, Samuel N.; Howell, Steve B.; Ziegler, Carl; Vrijmoet, Eliot Halley; Adams, Fred C.; Arney, Giada N.; Boyd, Patricia T.; Brande, Jonathan; Burke, Christopher J.; Cacciapuoti, Luca; Chance, Quadry; Christiansen, Jessie L.; Covone, Giovanni; Daylan, Tansu; Dineen, Danielle; Dressing, Courtney D.; Essack, Zahra; Fauchez, Thomas J.; Galgano, Brianna; Howe, Alex R.; Kaltenegger, Lisa; Kane, Stephen R.; Lam, Christopher; Lee, Eve J.; Lewis, Nikole K.; Logsdon, Sarah E.; Mandell, Avi M.; Monsue, Teresa; Mullally, Fergal; Mullally, Susan E.; Paudel, Rishi R.; Pidhorodetska, Daria; Plavchan, Peter; Reyes, Naylynn Tañón; Rinehart, Stephen A.; Rojas-Ayala, Bárbara; Smith, Jeffrey C.; Stassun, Keivan G.; Tenenbaum, Peter; Vega, Laura D.; Villanueva, Geronimo L.; Wolf, Eric T.; Youngblood, Allison; Ricker, George R.; Vanderspek, Roland K.; Latham, David W.; Seager, Sara; Winn, Joshua N.; Jenkins, Jon M.; Bakos, Gáspár Å.; Briceño, César; Ciardi, David R.; Cloutier, Ryan; Conti, Dennis M.; Couperus, Andrew; Di Sora, Mario; Eisner, Nora L.; Everett, Mark E.; Gan, Tianjun; Hartman, Joel D.; Henry, Todd; Isopi, Giovanni; Jao, Wei-Chun; Jensen, Eric L. N.; Law, Nicholas; Mallia, Franco; Matson, Rachel A.; Shappee, Benjamin J.; Le Wood, Mackennae; Winters, Jennifer G.
Abstract: We present the discovery and validation of a three-planet system orbiting the nearby (31.1 pc) M2 dwarf star TOI-700 (TIC 150428135). TOI-700 lies in the TESS continuous viewing zone in the Southern Ecliptic Hemisphere; observations spanning 11 sectors reveal three planets with radii ranging from 1 R_⊕ to 2.6 R_⊕ and orbital periods ranging from 9.98 to 37.43 days. Ground-based follow-up combined with diagnostic vetting and validation tests enables us to rule out common astrophysical false-positive scenarios and validate the system of planets. The outermost planet, TOI-700 d, has a radius of 1.19 ± 0.11 R_⊕ and resides within a conservative estimate of the host star's habitable zone, where it receives a flux from its star that is approximately 86% of Earth's insolation. In contrast to some other low-mass stars that host Earth-sized planets in their habitable zones, TOI-700 exhibits low levels of stellar activity, presenting a valuable opportunity to study potentially rocky planets over a wide range of conditions affecting atmospheric escape. While atmospheric characterization of TOI-700 d with the James Webb Space Telescope (JWST) will be challenging, the larger sub-Neptune, TOI-700 c (R = 2.63 R_⊕), will be an excellent target for JWST and future space-based observatories. TESS is scheduled to once again observe the Southern Hemisphere, and it will monitor TOI-700 for an additional 11 sectors in its extended mission. These observations should allow further constraints on the known planet parameters and searches for additional planets and transit timing variations in the system.