_version_ 1866913347628171264
author Silverstein, Michele L.
Barclay, Thomas
Schlieder, Joshua E.
Collins, Karen A.
Schwarz, Richard P.
Hord, Benjamin J.
Rowe, Jason F.
Kruse, Ethan
Astudillo-Defru, Nicola
Bonfils, Xavier
Caldwell, Douglas A.
Charbonneau, David
Cloutier, Ryan
Collins, Kevin I.
Daylan, Tansu
Fong, William
Jenkins, Jon M.
Kunimoto, Michelle
McDermott, Scott
Mergas, Felipe
Palle, Enric
Ricker, George R.
Seager, Sara
Shporer, Avi
Tey, Evan
Vanderspek, Roland
Winn, Joshua N.
author_facet Silverstein, Michele L.
Barclay, Thomas
Schlieder, Joshua E.
Collins, Karen A.
Schwarz, Richard P.
Hord, Benjamin J.
Rowe, Jason F.
Kruse, Ethan
Astudillo-Defru, Nicola
Bonfils, Xavier
Caldwell, Douglas A.
Charbonneau, David
Cloutier, Ryan
Collins, Kevin I.
Daylan, Tansu
Fong, William
Jenkins, Jon M.
Kunimoto, Michelle
McDermott, Scott
Mergas, Felipe
Palle, Enric
Ricker, George R.
Seager, Sara
Shporer, Avi
Tey, Evan
Vanderspek, Roland
Winn, Joshua N.
contents 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 HR 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 multi-planet 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 Earth radii planet in a 4.97-day orbit, with an insolation flux of 9.1 +0.9/-0.8 Earth insolations. 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 multi-planet systems around M dwarfs makes the system a valuable benchmark for testing theories of planet formation and evolution.
format Preprint
id arxiv_https___arxiv_org_abs_2403_00110
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Validation of a Third Planet in the LHS 1678 System
Silverstein, Michele L.
Barclay, Thomas
Schlieder, Joshua E.
Collins, Karen A.
Schwarz, Richard P.
Hord, Benjamin J.
Rowe, Jason F.
Kruse, Ethan
Astudillo-Defru, Nicola
Bonfils, Xavier
Caldwell, Douglas A.
Charbonneau, David
Cloutier, Ryan
Collins, Kevin I.
Daylan, Tansu
Fong, William
Jenkins, Jon M.
Kunimoto, Michelle
McDermott, Scott
Mergas, Felipe
Palle, Enric
Ricker, George R.
Seager, Sara
Shporer, Avi
Tey, Evan
Vanderspek, Roland
Winn, Joshua N.
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
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 HR 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 multi-planet 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 Earth radii planet in a 4.97-day orbit, with an insolation flux of 9.1 +0.9/-0.8 Earth insolations. 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 multi-planet systems around M dwarfs makes the system a valuable benchmark for testing theories of planet formation and evolution.
title Validation of a Third Planet in the LHS 1678 System
topic Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2403.00110