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Author (up) Addison, BC.; Wright, DJ.; Nicholson, BA.; Cale, B.; Mocnik, T.; Huber, D.; Plavchan, P.; Wittenmyer, RA.; Vanderburg, A.; Chaplin, WJ.; Chontos, A.; Clark, JT.; Eastman, JD.; Ziegler, C.; Brahm, R.; Carter, BD.; Clerte, M.; Espinoza, N.; Horner, J.; Bentley, J.; Jordan, A.; Kane, SR.; Kielkopf, JF.; Laychock, E.; Mengel, MW.; Okumura, J.; Stassun, KG.; Bedding, TR.; Bowler, BP.; Burnelis, A.; Blanco-Cuaresma, S.; Collins, M.; Crossfield, I.; Davis, AB.; Evensberget, D.; Heitzmann, A.; Howell, SB.; Law, N.; Mann, AW.; Marsden, SC.; Matson, RA.; O'Connor, JH.; Shporer, A.; Stevens, C.; Tinney, CG.; Tylor, C.; Wang, SH.; Zhang, H.; Henning, T.; Kossakowski, D.; Ricker, G.; Sarkis, P.; Schlecker, M.; Torres, P.; Vanderspek, R.; Latham, DW.; Seager, S.; Winn, JN.; Jenkins, JM.; Mireles, I.; Rowden, P.; Pepper, J.; Daylan, T.; Schlieder, JE.; Collins, KA.; Collins, KI.; Tan, TG.; Ball, WH.; Basu, S.; Buzasi, DL.; Campante, TL.; Corsaro, E.; Gonzalez-Cuesta, L.; Davies, GR.; de Almeida, L.; do Nascimento, JD.; Garcia, RA.; Guo, Z.; Handberg, R.; Hekker, S.; Hey, DR.; Kallinger, T.; Kawaler, SD.; Kayhan, C.; Kuszlewicz, JS.; Lund, MN.; Lyttle, A.; Mathur, S.; Miglio, A.; Mosser, B.; Nielsen, MB.; Serenelli, AM.; Aguirre, VS.; Themessl, N.
Title TOI-257b (HD 19916b): a warm sub-saturn orbiting an evolved F-type star Type
Year 2021 Publication Monthly Notices Of The Royal Astronomical Society Abbreviated Journal Mon. Not. Roy. Astron. Soc.
Volume 502 Issue 3 Pages 3704-3722
Keywords asteroseismology; techniques: photometric; techniques: radial velocities; techniques: spectroscopic; planetary systems; stars: individual (TIC 200723869/TOI-257)
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 +/- 0.023M(J) (43.9 +/- 7.3 M-circle plus), a radius of R-P = 0.639 +/- 0.013 R-J (7.16 +/- 0.15 R-circle plus), bulk density of 0.65(-0.11)(+0.12) (cgs), and period 18.38818(-0.00084)(+0.00085) days. TOI-257b orbits a bright (V = 7.612 mag) somewhat evolved late F-type star with M-* = 1.390 +/- 0.046(Msun), R-* = 1.888 +/- 0.033 R-sun, T-eff = 6075 +/- 90 K, and vsin i = 11.3 +/- 0.5 kms(-1). Additionally, we find hints for a second non-transiting sub-Saturn mass planet on a similar to 71 day orbit using the radial velocity data. This system joins the ranks of a small number of exoplanet host stars (similar to 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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0035-8711 ISBN Medium
Area Expedition Conference
Notes WOS:000648998800038 Approved
Call Number UAI @ alexi.delcanto @ Serial 1397
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Author (up) Grieves, N.; Bouchy, F.; Lendl, M.; Carmichael, T.; Mireles, I.; Shporer, A.; McLeod, K.K.; Collins, K.A .; Brahm, R.; Stassun, K.G.; Gill, S.; Bouma, L.G.; Guillot, T.; Cointepas, M.; Dos Santos, L.A.; Casewell, S.L.; Jenkins, J.M.; Henning, T.; Nielsen, L.D. Psaridi, A.; Udry, S.; Segransan, D.; Eastman, J.D.; Zhou, G.; Abe, L.; Agabi, A.; Bakos, G.; Charbonneau, D.; Collins, K.I.; Colon, K.D.; Crouzet, N.; Dransfield, G.; Evans, P.; Goeke, R.F.; Hart, R:, Irwin, J.M.; Jensen, E.L.N.; Jordan, A.; Kielkopf, J.F.; Latham, D.W.; Marie-Sainte, W:, Mekarnia, D.; Nelson, P.; Quinn, S.N.; Radford, D.J.; Rodriguez, D.R.; Rowden, P.; Schmider, F.X.; Schwarz, R.P.; Smith, J.C.; Stockdale, C.; Suarez, O.; Tan, T.G.; Triaud, A.H.M.J.; Waalkes, W.; Wingham, G.
Title Populating the brown dwarf and stellar boundary: Five stars with transiting companions near the hydrogen-burning mass limit Type
Year 2021 Publication Astronomy & Astrophysics Abbreviated Journal Astron. Astrophys.
Volume 652 Issue Pages
Keywords brown dwarfs; stars; low-mass; binaries: eclipsing
Abstract We report the discovery of five transiting companions near the hydrogen-burning mass limit in close orbits around main sequence stars originally identified by the Transiting Exoplanet Survey Satellite (TESS) as TESS objects of interest (TOIs): TOI-148, TOI-587, TOI-681, TOI-746, and TOI-1213. Using TESS and ground-based photometry as well as radial velocities from the CORALIE, CHIRON, TRES, and FEROS spectrographs, we found the companions have orbital periods between 4.8 and 27.2 days, masses between 77 and 98 M-Jup , and radii between 0.81 and 1.66 R-Jup . These targets have masses near the uncertain lower limit of hydrogen core fusion (similar to 73-96 M-Jup ), which separates brown dwarfs and low-mass stars. We constrained young ages for TOI-587 (0.2 +/- 0.1 Gyr) and TOI-681 (0.17 +/- 0.03 Gyr) and found them to have relatively larger radii compared to other transiting companions of a similar mass. Conversely we estimated older ages for TOI-148 and TOI-746 and found them to have relatively smaller companion radii. With an effective temperature of 9800 +/- 200 K, TOI-587 is the hottest known main-sequence star to host a transiting brown dwarf or very low-mass star. We found evidence of spin-orbit synchronization for TOI-148 and TOI-746 as well as tidal circularization for TOI-148. These companions add to the population of brown dwarfs and very low-mass stars with well measured parameters ideal to test formation models of these rare objects, the origin of the brown dwarf desert, and the distinction between brown dwarfs and hydrogen-burning main sequence stars.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0004-6361 ISBN Medium
Area Expedition Conference
Notes WOS:000686774100006 Approved
Call Number UAI @ alexi.delcanto @ Serial 1461
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