The Astronomical Journal (Jan 2024)
Validation of a Third Planet in the LHS 1678 System
- Michele L. Silverstein,
- Thomas Barclay,
- Joshua E. Schlieder,
- Karen A. Collins,
- Richard P. Schwarz,
- Benjamin J. Hord,
- Jason F. Rowe,
- Ethan Kruse,
- Nicola Astudillo-Defru,
- Xavier Bonfils,
- Douglas A. Caldwell,
- David Charbonneau,
- Ryan Cloutier,
- Kevin I. Collins,
- Tansu Daylan,
- William Fong,
- Jon M. Jenkins,
- Michelle Kunimoto,
- Scott McDermott,
- Felipe Murgas,
- Enric Palle,
- George R. Ricker,
- Sara Seager,
- Avi Shporer,
- Evan Tey,
- Roland Vanderspek,
- Joshua N. Winn
Affiliations
- Michele L. Silverstein
- ORCiD
- University of Maryland , Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA; NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA; GSFC Sellers Exoplanet Environments Collaboration , Greenbelt, MD 20771, USA
- Thomas Barclay
- ORCiD
- NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA
- Joshua E. Schlieder
- ORCiD
- NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA
- Karen A. Collins
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA, 02138, USA
- Richard P. Schwarz
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA, 02138, USA
- Benjamin J. Hord
- ORCiD
- NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA
- Jason F. Rowe
- ORCiD
- Department of Physics and Astronomy, Bishops University , 2600 Rue College, Sherbrooke, QC J1M 1Z7, Canada
- Ethan Kruse
- ORCiD
- NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA; University of Maryland , College Park, MD 20742, USA
- Nicola Astudillo-Defru
- ORCiD
- Departamento de Matemática y Física Aplicadas, Universidad Católica de la Santísima Concepción , Alonso de Rivera 2850, Concepción, Chile
- Xavier Bonfils
- ORCiD
- Univ. Grenoble Alpes , CNRS, IPAG, F-38000 Grenoble, France
- Douglas A. Caldwell
- ORCiD
- SETI Institute , Mountain View, CA 94043 USA; NASA Ames Research Center , Moffett Field, CA 94035 USA
- David Charbonneau
- ORCiD
- Center for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA, 02138, USA
- Ryan Cloutier
- ORCiD
- Department of Physics & Astronomy, McMaster University , 1280 Main Street West, Hamilton, ON, L8S 4L8, Canada
- Kevin I. Collins
- ORCiD
- George Mason University , 4400 University Drive, Fairfax, VA, 22030 USA
- Tansu Daylan
- ORCiD
- Department of Physics and McDonnell Center for the Space Sciences, Washington University , St. Louis, MO 63130, USA
- William Fong
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Jon M. Jenkins
- ORCiD
- NASA Ames Research Center , Moffett Field, CA 94035, USA
- Michelle Kunimoto
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Scott McDermott
- Proto-Logic LLC , 1718 Euclid Street NW, Washington, DC 20009, USA
- Felipe Murgas
- ORCiD
- Instituto de Astrofísica de Canarias (IAC) , E-38205 La Laguna, Tenerife, Spain; Departamento de Astrofísica, Universidad de La Laguna (ULL) , E-38206 La Laguna, Tenerife, Spain
- Enric Palle
- ORCiD
- Instituto de Astrofísica de Canarias (IAC) , E-38205 La Laguna, Tenerife, Spain; Departamento de Astrofísica, Universidad de La Laguna (ULL) , E-38206 La Laguna, Tenerife, Spain
- George R. Ricker
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, 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 , MIT, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Avi Shporer
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Evan Tey
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Roland Vanderspek
- ORCiD
- Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
- Joshua N. Winn
- ORCiD
- Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08544, USA
- DOI
- https://doi.org/10.3847/1538-3881/ad3040
- Journal volume & issue
-
Vol. 167,
no. 6
p. 255
Abstract
The nearby LHS 1678 (TOI-696) system contains two confirmed planets and a wide-orbit, likely brown-dwarf companion, which orbit an M2 dwarf with a unique evolutionary history. The host star occupies a narrow “gap” in the Hertzsprung–Russell diagram lower main sequence, associated with the M dwarf fully convective boundary and long-term luminosity fluctuations. This system is one of only about a dozen M dwarf multiplanet systems to date that hosts an ultra-short-period planet (USP). Here we validate and characterize a third planet in the LHS 1678 system using TESS Cycle 1 and 3 data and a new ensemble of ground-based light curves. LHS 1678 d is a 0.98 ± 0.07 R _⊕ planet in a 4.97 day orbit, with an insolation flux of ${9.1}_{-0.8}^{+0.9}\,{S}_{\oplus }$ . These properties place it near 4:3 mean motion resonance with LHS 1678 c and in company with LHS 1678 c in the Venus zone. LHS 1678 c and d are also twins in size and predicted mass, making them a powerful duo for comparative exoplanet studies. LHS 1678 d joins its siblings as another compelling candidate for atmospheric measurements with the JWST and mass measurements using high-precision radial velocity techniques. Additionally, USP LHS 1678 b breaks the “peas-in-a-pod” trend in this system although additional planets could fill in the “pod” beyond its orbit. LHS 1678's unique combination of system properties and their relative rarity among the ubiquity of compact multiplanet systems around M dwarfs makes the system a valuable benchmark for testing theories of planet formation and evolution.
Keywords
