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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.
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Corporate Author Thesis
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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) Bergmann, C.; Jones, MI.; Zhao, J.; Mustill, AJ.; Brahm, R.; Torres, P.; Wittenmyer, RA.; Gunn, F.; Pollard, KR.; Zapata, A.; Vanzi, L.; Wang, SH.
Title HD 76920 b pinned down: A detailed analysis of the most eccentric planetary system around an evolved star Type
Year 2021 Publication Publications of the Astronomical Society of Australia Abbreviated Journal PUBL. ASTRON. SOC. AUST.
Volume 38 Issue Pages e019
Keywords EXTRA-SOLAR PLANETS; RADIAL-VELOCITY; GIANT STAR; STELLAR EVOLUTION; MASS COMPANION; EXOPLANETS; PRECISION; SEARCH; TRANSIT; I.
Abstract We present 63 new multi-site radial velocity (RV) measurements of the K1III giant HD 76920, which was recently reported to host the most eccentric planet known to orbit an evolved star. We focused our observational efforts on the time around the predicted periastron passage and achieved near-continuous phase coverage of the corresponding RV peak. By combining our RV measurements from four different instruments with previously published ones, we confirm the highly eccentric nature of the system and find an even higher eccentricity of , an orbital period of 415.891(-0.039)(+0.043) d, and a minimum mass of 3.13(-0.43)(+0.41) M-J for the planet. The uncertainties in the orbital elements are greatly reduced, especially for the period and eccentricity. We also performed a detailed spectroscopic analysis to derive atmospheric stellar parameters, and thus the fundamental stellar parameters (M-*, R-*, L-*) taking into account the parallax from Gaia DR2, and independently determined the stellar mass and radius using asteroseismology. Intriguingly, at periastron, the planet comes to within 2.4 stellar radii of its host star's surface. However, we find that the planet is not currently experiencing any significant orbital decay and will not be engulfed by the stellar envelope for at least another 50-80 Myr. Finally, while we calculate a relatively high transit probability of 16%, we did not detect a transit in the TESS photometry.
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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 ISBN Medium
Area Expedition Conference
Notes WOS:000642222500001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1379
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