_version_ 1866915815144554496
author Li, Yaguang
Liu, Michael C.
Dupuy, Trent J.
Huber, Daniel
Zhang, Jingwen
Hey, Daniel
Costa, R. R.
Larsen, Jens Reersted
Ong, J. M. Joel
Basu, Sarbani
Metcalfe, Travis S.
Zhou, Yixiao
van Saders, Jennifer
Bedding, Timothy R.
Hon, Marc
Kjeldsen, Hans
Campante, Tiago L.
Monteiro, Mário J. P. F. G.
Lundkvist, Mia Sloth
Winther, Mark Lykke
Chontos, Ashley
Saunders, Nicholas
Carmichael, Theron W.
Bouchez, Antonin
Alvarez, Carlos
Walker, Samuel A. U.
Sepulveda, Aldo G.
Isaacson, Howard
Howard, Andrew W.
Gibson, Steven R.
Halverson, Samuel
Rider, Kodi
Roy, Arpita
Baker, Ashley D.
Edelstein, Jerry
Smith, Chris
Fulton, Benjamin J.
Walawender, Josh
author_facet Li, Yaguang
Liu, Michael C.
Dupuy, Trent J.
Huber, Daniel
Zhang, Jingwen
Hey, Daniel
Costa, R. R.
Larsen, Jens Reersted
Ong, J. M. Joel
Basu, Sarbani
Metcalfe, Travis S.
Zhou, Yixiao
van Saders, Jennifer
Bedding, Timothy R.
Hon, Marc
Kjeldsen, Hans
Campante, Tiago L.
Monteiro, Mário J. P. F. G.
Lundkvist, Mia Sloth
Winther, Mark Lykke
Chontos, Ashley
Saunders, Nicholas
Carmichael, Theron W.
Bouchez, Antonin
Alvarez, Carlos
Walker, Samuel A. U.
Sepulveda, Aldo G.
Isaacson, Howard
Howard, Andrew W.
Gibson, Steven R.
Halverson, Samuel
Rider, Kodi
Roy, Arpita
Baker, Ashley D.
Edelstein, Jerry
Smith, Chris
Fulton, Benjamin J.
Walawender, Josh
contents We present high-precision measurements for HR~7672AB, composed of a Sun-like (G0V) star and an L~dwarf companion. Three nights of precise (70 cm/s) radial velocity (RV) asteroseismology with the Keck Planet Finder clearly detect 5-minute oscillations from the primary HR~7672A, and modeling of the frequency spectrum yields an asteroseismic age of $1.87\pm0.65$~Gyr. We also determine a gyrochronological age of $2.58\pm0.47$~Gyr, and we combine these two results for a final age of $2.26\pm0.40$~Gyr. In addition, we obtained new RVs for HR~7672A and new astrometry for the companion HR~7672B. From a joint orbit fit, we measured a dynamical mass of $1.111\pm0.017$~$\text{M}_\odot$ for HR~7672A and $75.39\pm0.67$~$\text{M}_{\text{Jup}}$ for HR~7672B. This places the companion near the stellar/substellar boundary and thus particularly sensitive to differences in model predictions. The joint precision in host star age (18\% uncertainty) and companion mass (0.9\% uncertainty) makes HR~7672AB an exceptional substellar benchmark. Combined with the companion's luminosity, we use these measurements to test predictions from six brown dwarf cooling models. The best agreement occurs with the Chabrier et al. (2023) models, which incorporate a new equation of state, resulting in predictions that agree within $<$0.3$σ$ with all the observations. The other 5 sets of models agree at the 1--3$σ$ level depending on the particular test, and some models struggle to predict a sufficient low luminosity for HR~7672B at any age given its dynamical mass. We also detected a weak seismic signal in near-simultaneous TESS photometry of HR~7672A, with the resulting RV-to-photometry oscillation amplitude ratio consistent with solar values.
format Preprint
id arxiv_https___arxiv_org_abs_2512_06083
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Test of Substellar Evolutionary Models with High-Precision Ages from Asteroseismology and Gyrochronology for the Benchmark System HR 7672AB
Li, Yaguang
Liu, Michael C.
Dupuy, Trent J.
Huber, Daniel
Zhang, Jingwen
Hey, Daniel
Costa, R. R.
Larsen, Jens Reersted
Ong, J. M. Joel
Basu, Sarbani
Metcalfe, Travis S.
Zhou, Yixiao
van Saders, Jennifer
Bedding, Timothy R.
Hon, Marc
Kjeldsen, Hans
Campante, Tiago L.
Monteiro, Mário J. P. F. G.
Lundkvist, Mia Sloth
Winther, Mark Lykke
Chontos, Ashley
Saunders, Nicholas
Carmichael, Theron W.
Bouchez, Antonin
Alvarez, Carlos
Walker, Samuel A. U.
Sepulveda, Aldo G.
Isaacson, Howard
Howard, Andrew W.
Gibson, Steven R.
Halverson, Samuel
Rider, Kodi
Roy, Arpita
Baker, Ashley D.
Edelstein, Jerry
Smith, Chris
Fulton, Benjamin J.
Walawender, Josh
Solar and Stellar Astrophysics
Earth and Planetary Astrophysics
We present high-precision measurements for HR~7672AB, composed of a Sun-like (G0V) star and an L~dwarf companion. Three nights of precise (70 cm/s) radial velocity (RV) asteroseismology with the Keck Planet Finder clearly detect 5-minute oscillations from the primary HR~7672A, and modeling of the frequency spectrum yields an asteroseismic age of $1.87\pm0.65$~Gyr. We also determine a gyrochronological age of $2.58\pm0.47$~Gyr, and we combine these two results for a final age of $2.26\pm0.40$~Gyr. In addition, we obtained new RVs for HR~7672A and new astrometry for the companion HR~7672B. From a joint orbit fit, we measured a dynamical mass of $1.111\pm0.017$~$\text{M}_\odot$ for HR~7672A and $75.39\pm0.67$~$\text{M}_{\text{Jup}}$ for HR~7672B. This places the companion near the stellar/substellar boundary and thus particularly sensitive to differences in model predictions. The joint precision in host star age (18\% uncertainty) and companion mass (0.9\% uncertainty) makes HR~7672AB an exceptional substellar benchmark. Combined with the companion's luminosity, we use these measurements to test predictions from six brown dwarf cooling models. The best agreement occurs with the Chabrier et al. (2023) models, which incorporate a new equation of state, resulting in predictions that agree within $<$0.3$σ$ with all the observations. The other 5 sets of models agree at the 1--3$σ$ level depending on the particular test, and some models struggle to predict a sufficient low luminosity for HR~7672B at any age given its dynamical mass. We also detected a weak seismic signal in near-simultaneous TESS photometry of HR~7672A, with the resulting RV-to-photometry oscillation amplitude ratio consistent with solar values.
title A Test of Substellar Evolutionary Models with High-Precision Ages from Asteroseismology and Gyrochronology for the Benchmark System HR 7672AB
topic Solar and Stellar Astrophysics
Earth and Planetary Astrophysics
url https://arxiv.org/abs/2512.06083