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Author 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 1323-3580 ISBN Medium
Area Expedition Conference
Notes WOS:000642222500001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1379
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Author Eberhardt, J.; Trifonov, T.; Kurster, M.; Stock, S.; Henning, T.; Wollbold, A.; Reffert, S.; Lee, M.H.; Zechmeister, M.; Rodler, F.; Zakhozhay, O.; Heeren, P.; Gandolfi, D.; Barragan, O.; Pinto, M.T.; Wolthoff, V.; Sarkis, P.; Brems, S.S.
Title Dynamical Architecture of the HD 107148 Planetary System Type
Year 2022 Publication Astronomical Journal Abbreviated Journal Astron. J.
Volume 163 Issue 5 Pages 198
Keywords LOMB-SCARGLE PERIODOGRAM; EXTRA-SOLAR PLANETS; RADIAL-VELOCITIES; ORBITAL SOLUTIONS; CARMENES SEARCH; M DWARFS; COMPANIONS; PRECISION; STARS; EXOPLANETS
Abstract We present an independent Doppler validation and dynamical orbital analysis of the two-planet system HD 107148, which was recently announced in Rosenthal et al. Our detailed analyses are based on literature HIRES data and newly obtained HARPS and CARMENES radial-velocity (RV) measurements as part of our survey in search for additional planets around single-planet systems. We perform a periodogram analysis of the available HIRES and HARPS precise RVs and stellar activity indicators. We do not find any apparent correlation between the RV measurements and the stellar activity indicators, thus linking the two strong periodicities to a moderately compact multiplanet system. We carry out orbital fitting analysis by testing various one- and two-planet orbital configurations and studying the posterior probability distribution of the fitted parameters. Our results solidify the existence of a Saturn-mass planet (HD 107148b, discovered first) with a period of P (b) similar to 77.2 days and a second, eccentric (e (c) similar to 0.4), Neptune-mass exoplanet (HD 107148c) with an orbital period of P (c) similar to 18.3 days. Finally, we investigate the two-planet system's long-term stability and overall orbital dynamics with the posterior distribution of our preferred orbital configuration. Our N-body stability simulations show that the system is long-term stable and exhibits large secular osculations in eccentricity but in no particular mean motion resonance configuration. The HD 107148 system, consisting of a solar-type main-sequence star with two giant planets in a rare configuration, features a common proper-motion white dwarf companion and is therefore a valuable target for understanding the formation and evolution of planetary systems.
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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 0004-6256 ISBN Medium
Area Expedition Conference
Notes WOS:000778725000001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1562
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