Companions to Kepler giant stars

• Verfasst von: Karjalainen, Marie [VerfasserIn]
• Verfasst von: Karjalainen, Raine [VerfasserIn]
• Verfasst von: Hatzes, Artie P. [VerfasserIn]
• Verfasst von: Lehmann, Holger [VerfasserIn]
• Verfasst von: Kervella, Pierre [VerfasserIn]
• Verfasst von: Hekker, Saskia [VerfasserIn]
• Verfasst von: Winckel, Hans Van [VerfasserIn]
• Verfasst von: Überlauer, Jakub [VerfasserIn]
• Verfasst von: Vítková, Michaela [VerfasserIn]
• Verfasst von: Skarka, Marek [VerfasserIn]
• Verfasst von: Kabáth, Petr [VerfasserIn]
• Verfasst von: Prins, Saskia [VerfasserIn]
• Verfasst von: Tkachenko, Andrew [VerfasserIn]
• Verfasst von: Cochran, William D. [VerfasserIn]
• Verfasst von: Jorissen, Alain [VerfasserIn]
• Titel: Companions to Kepler giant stars
• Titelzusatz: a long-period eccentric sub-stellar companion to KIC 3526061 and a stellar companion to HD 187878
• Verf.angabe: Marie Karjalainen, Raine Karjalainen, Artie P. Hatzes, Holger Lehmann, Pierre Kervella, Saskia Hekker, Hans Van Winckel, Jakub Überlauer, Michaela Vítková, Marek Skarka, Petr Kabáth, Saskia Prins, Andrew Tkachenko, William D. Cochran, and Alain Jorissen
• E-Jahr: 2022
• Jahr: 29 November 2022
• Umfang: 14 S.
• Fussnoten: Gesehen am 20.03.2023
• Titel Quelle: Enthalten in: Astronomy and astrophysics
• Ort Quelle: Les Ulis : EDP Sciences, 1969
• Jahr Quelle: 2022
• Band/Heft Quelle: 668(2022), Artikel-ID 26, Seite 1-14
• ISSN Quelle: 1432-0746
• DOI: doi:10.1051/0004-6361/202244501
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 183956296X

Abstract

<i>Context.<i/> Our knowledge of populations and the occurrence of planets orbiting evolved intermediate-mass stars is still incomplete. In 2010 we started a planet search programme among 95 giant stars observed by the <i>Kepler<i/> mission to increase the sample of giant stars with planets and with reliable estimates of stellar masses and radii.<i>Aims.<i/> We present the two systems from our planet search programme whose companions we were able to characterise: KIC 3526061 and HD 187878.<i>Methods.<i/> We used precise stellar radial velocity measurements taken with four different echelle spectrographs to derive an orbital solution. We used <i>Gaia<i/> astrometric measurements to obtain the inclination of the HD 187878 system and <i>Kepler<i/> photometric observations to estimate the stellar mass and radius.<i>Results.<i/> We report the discovery of a sub-stellar companion and a stellar companion around two intermediate-mass red giant branch stars. KIC 3526061 b is most likely a brown dwarf with a minimum mass of 18.15 ± 0.44 <i>M<i/><sub>Jupiter<sub/> in a long-period eccentric orbit, with orbital period d and orbital eccentricity <i>e<i/> = 0.85 ± 0.01. It is the most evolved system found having a sub-stellar companion with such a high eccentricity and wide separation. HD 187878 B has a minimum mass of 78.4 ± 2.0 <i>M<i/><sub>Jupiter<sub/>. Combining the spectroscopic orbital parameters with the astrometric proper motion anomaly, we derived an orbital inclination deg, which corresponds to the companion’s mass in the stellar regime of .<i>Conclusions.<i/> A sub-stellar companion of KIC 3526061 extends the sample of known red giant branch stars with sub-stellar companions on very eccentric wide orbits, and might provide a probe of the dynamical evolution of such systems over time.