TESS Asteroseismic Analysis of HD 76920: The Giant Star Hosting an Extremely Eccentric Exoplanet

Chen Jiang*, Tao Wu, Adina D. Feinstein, Keivan G. Stassun, Timothy R. Bedding, Dimitri Veras, Enrico Corsaro, Derek L. Buzasi, Dennis Stello, Yaguang Li, Savita Mathur, Rafael A. García, Sylvain N. Breton, Mia S. Lundkvist, Przemysław J. Mikołajczyk, Charlotte Gehan, Tiago L. Campante, Diego Bossini, Stephen R. Kane, Jia Mian Joel OngMutlu Yıldız, Cenk Kayhan, Zeynep Çelik Orhan, Sibel Örtel, Xinyi Zhang, Margarida S. Cunha, Bruno Lustosa de Moura, Jie Yu, Daniel Huber, Jian Wen Ou, Robert A. Wittenmyer, Laurent Gizon, William J. Chaplin

*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

Abstract

The Transiting Exoplanet Survey Satellite (TESS) mission searches for new exoplanets. The observing strategy of TESS results in high-precision photometry of millions of stars across the sky, allowing for detailed asteroseismic studies of individual systems. In this work, we present a detailed asteroseismic analysis of the giant star HD 76920 hosting a highly eccentric giant planet (e = 0.878) with an orbital period of 415 days, using five sectors of TESS light curve that cover around 140 days of data. Solar-like oscillations in HD 76920 are detected around 52 μHz by TESS for the first time. By utilizing asteroseismic modeling that takes classical observational parameters and stellar oscillation frequencies as constraints, we determine improved measurements of the stellar mass (1.22 ± 0.11 M ), radius (8.68 ± 0.34 R ), and age (5.2 ± 1.4 Gyr). With the updated parameters of the host star, we update the semimajor axis and mass of the planet as a = 1.165 ± 0.035 au and M p sin i = 3.57 ± 0.22 M Jup . With an orbital pericenter of 0.142 ± 0.005 au, we confirm that the planet is currently far away enough from the star to experience negligible tidal decay until being engulfed in the stellar envelope. We also confirm that this event will occur within about 100 Myr, depending on the stellar model used.

Original languageEnglish
Article number20
JournalAstrophysical Journal
Volume945
Issue1
Number of pages12
ISSN0004-637X
DOIs
Publication statusPublished - Mar 2023

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