The Astronomical Journal (Jan 2022)

TOI 560: Two Transiting Planets Orbiting a K Dwarf Validated with iSHELL, PFS, and HIRES RVs

  • Mohammed El Mufti,
  • Peter P. Plavchan,
  • Howard Isaacson,
  • Bryson L. Cale,
  • Dax L. Feliz,
  • Michael A. Reefe,
  • Coel Hellier,
  • Keivan Stassun,
  • Jason Eastman,
  • Alex Polanski,
  • Ian J. M. Crossfield,
  • Eric Gaidos,
  • Veselin Kostov,
  • Justin M. Wittrock,
  • Joel Villaseñor,
  • Joshua E. Schlieder,
  • Luke G. Bouma,
  • Kevin I. Collins,
  • Farzaneh Zohrabi,
  • Rena A. Lee,
  • Ahmad Sohani,
  • John Berberian,
  • David Vermilion,
  • Patrick Newman,
  • Claire Geneser,
  • Angelle Tanner,
  • Natalie M. Batalha,
  • Courtney Dressing,
  • Benjamin Fulton,
  • Andrew W. Howard,
  • Daniel Huber,
  • Stephen R. Kane,
  • Erik A. Petigura,
  • Paul Robertson,
  • Arpita Roy,
  • Lauren M. Weiss,
  • Aida Behmard,
  • Corey Beard,
  • Ashley Chontos,
  • Fei Dai,
  • Paul A. Dalba,
  • Tara Fetherolf,
  • Steven Giacalone,
  • Michelle L. Hill,
  • Lea A. Hirsch,
  • Rae Holcomb,
  • Jack Lubin,
  • Andrew Mayo,
  • Teo Močnik,
  • Joseph M. Akana Murphy,
  • Lee J. Rosenthal,
  • Ryan A. Rubenzahl,
  • Nicholas Scarsdale,
  • Christopher Stockdale,
  • Karen Collins,
  • Ryan Cloutier,
  • Howard Relles,
  • Thiam-Guan Tan,
  • Nicholas J Scott,
  • Zach Hartman,
  • Elisabeth Matthews,
  • David R. Ciardi,
  • Erica Gonzales,
  • Rachel A. Matson,
  • Charles Beichman,
  • Allyson Bieryla,
  • E. Furlan,
  • Crystal L. Gnilka,
  • Steve B. Howell,
  • Carl Ziegler,
  • César Briceño,
  • Nicholas Law,
  • Andrew W. Mann,
  • Markus Rabus,
  • Marshall C. Johnson,
  • Jessie Christiansen,
  • Laura Kreidberg,
  • David Anthony Berardo,
  • Drake Deming,
  • Varoujan Gorjian,
  • Farisa Y. Morales,
  • Björn Benneke,
  • Diana Dragomir,
  • Robert A. Wittenmyer,
  • Sarah Ballard,
  • Brendan P. Bowler,
  • Jonathan Horner,
  • John Kielkopf,
  • Huigen Liu,
  • Avi Shporer,
  • C. G. Tinney,
  • Hui Zhang,
  • Duncan J. Wright,
  • Brett C. Addison,
  • Matthew W. Mengel,
  • Jack Okumura

DOI
https://doi.org/10.3847/1538-3881/ac9834
Journal volume & issue
Vol. 165, no. 1
p. 10

Abstract

Read online

We validate the presence of a two-planet system orbiting the 0.15–1.4 Gyr K4 dwarf TOI 560 (HD 73583). The system consists of an inner moderately eccentric transiting mini-Neptune (TOI 560 b, $P={6.3980661}_{-0.0000097}^{+0.0000095}$ days, $e={0.294}_{-0.062}^{+0.13}$ , $M={0.94}_{-0.23}^{+0.31}{M}_{\mathrm{Nep}}$ ) initially discovered in the Sector 8 Transiting Exoplanet Survey Satellite (TESS) mission observations, and a transiting mini-Neptune (TOI 560 c, $P={18.8805}_{-0.0011}^{+0.0024}$ days, $M={1.32}_{-0.32}^{+0.29}{M}_{\mathrm{Nep}}$ ) discovered in the Sector 34 observations, in a rare near-1:3 orbital resonance. We utilize photometric data from TESS Spitzer, and ground-based follow-up observations to confirm the ephemerides and period of the transiting planets, vet false-positive scenarios, and detect the photoeccentric effect for TOI 560 b. We obtain follow-up spectroscopy and corresponding precise radial velocities (RVs) with the iSHELL spectrograph at the NASA Infrared Telescope Facility and the HIRES Spectrograph at Keck Observatory to validate the planetary nature of these signals, which we combine with published Planet Finder Spectrograph RVs from the Magellan Observatory. We detect the masses of both planets at >3 σ significance. We apply a Gaussian process (GP) model to the TESS light curves to place priors on a chromatic RV GP model to constrain the stellar activity of the TOI 560 host star, and confirm a strong wavelength dependence for the stellar activity demonstrating the ability of near-IR RVs to mitigate stellar activity for young K dwarfs. TOI 560 is a nearby moderately young multiplanet system with two planets suitable for atmospheric characterization with the James Webb Space Telescope and other upcoming missions. In particular, it will undergo six transit pairs separated by <6 hr before 2027 June.

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