TY - JOUR
T1 - Validation of a Third Planet in the LHS 1678 System
AU - Silverstein, Michele L.
AU - Barclay, Thomas
AU - Schlieder, Joshua E.
AU - Collins, Karen A.
AU - Schwarz, Richard P.
AU - Hord, Benjamin J.
AU - Rowe, Jason F.
AU - Kruse, Ethan
AU - Astudillo-Defru, Nicola
AU - Bonfils, Xavier
AU - Caldwell, Douglas A.
AU - Charbonneau, David
AU - Cloutier, Ryan
AU - Collins, Kevin I.
AU - Daylan, Tansu
AU - Fong, William
AU - Jenkins, Jon M.
AU - Kunimoto, Michelle
AU - McDermott, Scott
AU - Murgas, Felipe
AU - Palle, Enric
AU - Ricker, George R.
AU - Seager, Sara
AU - Shporer, Avi
AU - Tey, Evan
AU - Vanderspek, Roland
AU - Winn, Joshua N.
N1 - Publisher Copyright:
© 2024. The Author(s). Published by the American Astronomical Society.
PY - 2024/6/1
Y1 - 2024/6/1
N2 - 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 ⊕ . 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.
AB - 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 ⊕ . 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.
UR - http://www.scopus.com/inward/record.url?scp=85192751122&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85192751122&partnerID=8YFLogxK
U2 - 10.3847/1538-3881/ad3040
DO - 10.3847/1538-3881/ad3040
M3 - Article
AN - SCOPUS:85192751122
SN - 0004-6256
VL - 167
JO - Astronomical Journal
JF - Astronomical Journal
IS - 6
M1 - 255
ER -