TESS Giants Transiting Giants. I.: A Noninflated Hot Jupiter Orbiting a Massive Subgiant Journal Articles uri icon

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abstract

  • Abstract While the population of confirmed exoplanets continues to grow, the sample of confirmed transiting planets around evolved stars is still limited. We present the discovery and confirmation of a hot Jupiter orbiting TOI-2184 (TIC 176956893), a massive evolved subgiant (M ⋆ = 1.53 ± 0.12 M ⊙, R ⋆ = 2.90 ± 0.14 R ⊙) in the Transiting Exoplanet Survey Satellite (TESS) Southern Continuous Viewing Zone. The planet was flagged as a false positive by the TESS Quick-Look Pipeline due to periodic systematics introducing a spurious depth difference between even and odd transits. Using a new pipeline to remove background scattered light in TESS Full Frame Image data, we combine space-based TESS photometry, ground-based photometry, and ground-based radial velocity measurements to report a planet radius of R p = 1.017 ± 0.051 R J and mass of M p = 0.65 ± 0.16 M J . For a planet so close to its star, the mass and radius of TOI-2184b are unusually well matched to those of Jupiter. We find that the radius of TOI-2184b is smaller than theoretically predicted based on its mass and incident flux, providing a valuable new constraint on the timescale of post-main-sequence planet inflation. The discovery of TOI-2184b demonstrates the feasibility of detecting planets around faint (TESS magnitude > 12) post-main-sequence stars and suggests that many more similar systems are waiting to be detected in the TESS FFIs, whose confirmation may elucidate the final stages of planetary system evolution.

authors

  • Saunders, Nicholas
  • Grunblatt, Samuel K
  • Huber, Daniel
  • Collins, Karen A
  • Jensen, Eric LN
  • Vanderburg, Andrew
  • Brahm, Rafael
  • Jordán, Andrés
  • Espinoza, Néstor
  • Henning, Thomas
  • Hobson, Melissa J
  • Quinn, Samuel N
  • Zhou, George
  • Butler, R Paul
  • Crause, Lisa
  • Kuhn, Rudi B
  • Moses Mogotsi, K
  • Hellier, Coel
  • Angus, Ruth
  • Hattori, Soichiro
  • Chontos, Ashley
  • Ricker, George R
  • Jenkins, Jon M
  • Tenenbaum, Peter
  • Latham, David W
  • Seager, Sara
  • Vanderspek, Roland K
  • Winn, Joshua N
  • Stockdale, Chris
  • Cloutier, Ryan

publication date

  • February 1, 2022