TESS Giants Transiting Giants. III. An Eccentric Warm Jupiter Supports a Period−Eccentricity Relation for Giant Planets Transiting Evolved Stars

Samuel K. Grunblatt, Nicholas Saunders, Ashley Chontos, Soichiro Hattori, Dimitri Veras, Daniel Huber, Ruth Angus, Malena Rice, Katelyn Breivik, Sarah Blunt, Steven Giacalone, Jack Lubin, Howard Isaacson, Andrew W. Howard, David R. Ciardi, Boris S. Safonov, Ivan A. Strakhov, David W. Latham, Allyson Bieryla, George R. RickerJon M. Jenkins, Peter Tenenbaum, Avi Shporer, Edward H. Morgan, Veselin Kostov, Hugh P. Osborn, Diana Dragomir, Sara Seager, Roland K. Vanderspek, Joshua N. Winn

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The fate of planets around rapidly evolving stars is not well understood. Previous studies have suggested that, relative to the main-sequence population, planets transiting evolved stars (P < 100 days) tend to have more eccentric orbits. Here we present the discovery of TOI-4582 b, a 0.94 − 0.12 + 0.09 R J , 0.53 ± 0.05 M J planet orbiting an intermediate-mass subgiant star every 31.034 days. We find that this planet is also on a significantly eccentric orbit (e = 0.51 ± 0.05). We then compare the population of planets found transiting evolved (log g < 3.8) stars to the population of planets transiting main-sequence stars. We find that the rate at which median orbital eccentricity grows with period is significantly higher for evolved star systems than for otherwise similar main-sequence systems. In general, we observe that mean planet eccentricity 〈e〉 = a+blog10(P) for the evolved population with significant orbital eccentricity where a = −0.18 ± 0.08 and b = 0.38 ± 0.06, significantly distinct from the main-sequence planetary system population. This trend is seen even after controlling for stellar mass and metallicity. These systems do not appear to represent a steady evolution pathway from eccentric, long-period planetary orbits to circular, short-period orbits, as orbital model comparisons suggest that inspiral timescales are uncorrelated with orbital separation or eccentricity. Characterization of additional evolved planetary systems will distinguish effects of stellar evolution from those of stellar mass and composition.

Original languageEnglish (US)
Article number44
JournalAstronomical Journal
Volume165
Issue number2
DOIs
StatePublished - Feb 1 2023

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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