The TESS-Keck Survey. VIII. Confirmation of a Transiting Giant Planet on an Eccentric 261 day Orbit with the Automated Planet Finder Telescope
Creators: name: Dalba, Paul A.
name: Kane, Stephen R.
name: Dragomir, Diana
name: Villanueva, Steven
name: Collins, Karen A.
name: Jacobs, Thomas Lee
name: Lacourse, Daryll M.
name: Gagliano, Robert
name: Kristiansen, Martti H.
name: Omohundro, Mark
name: Schwengeler, Hans M.
name: Terentev, Ivan A.
name: Vanderburg, Andrew
name: Fulton, Benjamin
name: Isaacson, Howard
name: Van Zandt, Judah
name: Howard, Andrew W.
name: Thorngren, Daniel P.
name: Howell, Steve B.
name: Batalha, Natalie M.
name: Chontos, Ashley
name: Crossfield, Ian J. M.
name: Dressing, Courtney D.
name: Huber, Daniel
name: Petigura, Erik A.
name: Robertson, Paul
name: Roy, Arpita
name: Weiss, Lauren M.
name: Behmard, Aida
name: Beard, Corey
name: Brinkman, Casey L.
name: Giacalone, Steven
name: Hill, Michelle L.
name: Lubin, Jack
name: Mayo, Andrew W.
name: Močnik, Teo
name: Murphy, Joseph M. Akana
name: Polanski, Alex S.
name: Rice, Malena
name: Rosenthal, Lee J.
name: Rubenzahl, Ryan A.
name: Scarsdale, Nicholas
name: Turtelboom, Emma V.
name: Tyler, Dakotah
name: Benni, Paul
name: Boyce, Pat
name: Esposito, Thomas M.
name: Girardin, E.
name: Laloum, Didier
name: Lewin, Pablo
name: Mann, Christopher R.
name: Marchis, Franck
name: Schwarz, Richard P.
name: Srdoc, Gregor
name: Steuer, Jana
name: Sivarani, Thirupathi
name: Unni, Athira
name: Eisner, Nora L.
name: Fetherolf, Tara
name: Li, Zhexing
name: Yao, Xinyu
name: Pepper, Joshua
name: Ricker, George R.
name: Vanderspek, Roland
name: Latham, David W.
name: Seager, S.
name: Winn, Joshua N.
name: Jenkins, Jon M.
name: Burke, Christopher J.
name: Eastman, Jason D.
name: Lund, Michael B.
name: Rodriguez, David R.
name: Rowden, Pamela
name: Ting, Eric B.
name: Villaseñor, Jesus Noel
Publisher: name: arXiv
Year: 2022
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We report the discovery of TOI-2180 b, a 2.8 $M_{\rm J}$ giant planet orbiting a slightly evolved G5 host star. This planet transited only once in Cycle 2 of the primary Transiting Exoplanet Survey Satellite (TESS) mission. Citizen scientists identified the 24 hr single-transit event shortly after the data were released, allowing a Doppler monitoring campaign with the Automated Planet Finder telescope at Lick Observatory to begin promptly. The radial velocity observations refined the orbital period of TOI-2180 b to be 260.8$\pm$0.6 days, revealed an orbital eccentricity of 0.368$\pm$0.007, and discovered long-term acceleration from a more distant massive companion. We conducted ground-based photometry from 14 sites spread around the globe in an attempt to detect another transit. Although we did not make a clear transit detection, the nondetections improved the precision of the orbital period. We predict that TESS will likely detect another transit of TOI-2180 b in Sector 48 of its extended mission. We use giant planet structure models to retrieve the bulk heavy-element content of TOI-2180 b. When considered alongside other giant planets with orbital periods over 100 days, we find tentative evidence that the correlation between planet mass and metal enrichment relative to stellar is dependent on orbital properties. Single-transit discoveries like TOI-2180 b highlight the exciting potential of the TESS mission to find planets with long orbital periods and low irradiation fluxes despite the selection biases associated with the transit method.
description: Published in AJ