The Astrophysical Journal Letters (Jan 2023)
Separated Twins or Just Siblings? A Multiplanet System around an M Dwarf Including a Cool Sub-Neptune
- Mallory Harris,
- Diana Dragomir,
- Ismael Mireles,
- Karen A. Collins,
- Solène Ulmer-Moll,
- Steve B. Howell,
- Keivan G. Stassun,
- George Zhou,
- Carl Ziegler,
- François Bouchy,
- César Briceño,
- David Charbonneau,
- Kevin I. Collins,
- Gábor Fűűrész,
- Natalia M. Guerrero,
- Jon M. Jenkins,
- Eric L. N. Jensen,
- Martti H. K. Kristiansen,
- Nicholas Law,
- Monika Lendl,
- Andrew W. Mann,
- Hugh P. Osborn,
- Samuel N. Quinn,
- George R. Ricker,
- Richard P. Schwarz,
- Sara Seager,
- Eric B. Ting,
- Roland Vanderspek,
- David Watanabe,
- Joshua N. Winn
Affiliations
- Mallory Harris
- ORCiD
- Department of Physics and Astronomy, University of New Mexico , Albuquerque, NM, USA
- Diana Dragomir
- ORCiD
- Department of Physics and Astronomy, University of New Mexico , Albuquerque, NM, USA
- Ismael Mireles
- ORCiD
- Department of Physics and Astronomy, University of New Mexico , Albuquerque, NM, USA
- Karen A. Collins
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- Solène Ulmer-Moll
- Observatoire de Genève, Université de Genève , Chemin Pegasi 51, CH-1290 Sauverny, Switzerland; Physikalisches Institut, University of Bern , Gesellschaftsstrasse 6, 3012 Bern, Switzerland
- Steve B. Howell
- ORCiD
- NASA Ames Research Center , Moffett Field, CA 94035, USA
- Keivan G. Stassun
- ORCiD
- Department of Physics and Astronomy, Vanderbilt University , Nashville, TN 37235, USA
- George Zhou
- ORCiD
- Centre for Astrophysics ∣ University of Southern Queensland , Toowoomba, QLD, Australia
- Carl Ziegler
- ORCiD
- Department of Physics, Engineering and Astronomy, Stephen F. Austin State University , 1936 North Street, Nacogdoches, TX 75962, USA
- François Bouchy
- ORCiD
- Observatoire de Genève, Université de Genève , Chemin Pegasi 51, CH-1290 Sauverny, Switzerland
- César Briceño
- ORCiD
- Cerro Tololo Inter-American Observatory , Casilla 603, La Serena, Chile
- David Charbonneau
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- Kevin I. Collins
- ORCiD
- George Mason University , 4400 University Drive, Fairfax, VA 22030, USA
- Gábor Fűűrész
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Natalia M. Guerrero
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA; Department of Astronomy, University of Florida , Gainesville, FL 32611, USA
- Jon M. Jenkins
- ORCiD
- NASA Ames Research Center , Moffett Field, CA 94035, USA
- Eric L. N. Jensen
- ORCiD
- Department of Physics & Astronomy, Swarthmore College , Swarthmore, PA 19081, USA
- Martti H. K. Kristiansen
- ORCiD
- Brorfelde Observatory , Observator Gyldenkernes Vej 7, DK-4340 Tølløse, Denmark
- Nicholas Law
- ORCiD
- Department of Physics and Astronomy, The University of North Carolina at Chapel Hill , Chapel Hill, NC 27599-3255, USA
- Monika Lendl
- ORCiD
- Observatoire de Genève, Université de Genève , Chemin Pegasi 51, CH-1290 Sauverny, Switzerland
- Andrew W. Mann
- ORCiD
- Department of Physics and Astronomy, The University of North Carolina at Chapel Hill , Chapel Hill, NC 27599-3255, USA
- Hugh P. Osborn
- ORCiD
- Physikalisches Institut, University of Bern , Gesellschaftsstrasse 6, 3012 Bern, Switzerland; Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Samuel N. Quinn
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- George R. Ricker
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Richard P. Schwarz
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA
- Sara Seager
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA; Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology , Cambridge, MA 02139, USA; Department of Aeronautics and Astronautics, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Eric B. Ting
- ORCiD
- NASA Ames Research Center , Moffett Field, CA 94035, USA
- Roland Vanderspek
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- David Watanabe
- ORCiD
- Planetary Discoveries , Fredericksburg, VA 22405, USA
- Joshua N. Winn
- ORCiD
- Department of Astrophysical Sciences, Princeton University , Princeton, NJ 08544, USA
- DOI
- https://doi.org/10.3847/2041-8213/ad037d
- Journal volume & issue
-
Vol. 959,
no. 1
p. L1
Abstract
We report the discovery of two TESS sub-Neptunes orbiting the early M dwarf TOI-904 (TIC 261257684). Both exoplanets, TOI-904 b and c, were initially observed in TESS Sector 12 with twin sizes of ${2.426}_{-0.157}^{+0.163}$ and ${2.167}_{-0.118}^{+0.130}$ R _⊕ , respectively. Through observations in five additional sectors in the TESS primary mission and the first and second extended missions, the orbital periods of the planets were measured to be 10.887 ± 0.001 and 83.999 ± 0.001 days, respectively. Reconnaissance radial velocity measurements (taken with EULER/CORALIE and SMARTS/CHIRON) and high-resolution speckle imaging with adaptive optics (obtained from SOAR/HRCAM and Gemini South/ZORRO) show no evidence of an eclipsing binary or a nearby companion, which, together with the low false-positive probabilities calculated with the statistical validation software TRICERATOPS, establishes the planetary nature of these candidates. The outer planet, TOI-904 c, is the longest-period M dwarf exoplanet found by TESS, with an estimated equilibrium temperature of 217 K. As the three other validated planets with comparable host stars and orbital periods were observed by Kepler around much dimmer stars ( J _mag > 12), TOI-904 c, orbiting a brighter star ( J _mag = 9.6), is the coldest M dwarf planet easily accessible for atmospheric follow-up. Future mass measurements and transmission spectroscopy of the similar-sized planets in this system could determine whether they are also similar in density and composition, suggesting a common formation pathway, or whether they have distinct origins.
Keywords
- Exoplanet systems
- Exoplanet detection methods
- Exoplanet astronomy
- M dwarf stars
- Cold Neptunes
- Mini Neptunes
