TOI-5375 B: A Very Low Mass Star at the Hydrogen-Burning Limit Orbiting an Early M-type Star

Abstract

The TESS mission detected a companion orbiting TIC 71268730, categorized it as a planet candidate, and designated the system TOI-5375. Our follow-up analysis using radial velocity data from the Habitable-zone Planet Finder (HPF), photometric data from Red Buttes Observatory (RBO), and speckle imaging with NN-EXPLORE Exoplanet Stellar Speckle Imager (NESSI) determined that the companion is a very low mass star (VLMS) near the hydrogen-burning mass limit with a mass of 0.080$\pm{0.002} M_{\Sun}$ ($83.81\pm 2.10M_J$), a radius of 0.1114$^{+0.0048}_{-0.0050} R_{\Sun}$ (1.0841${}_{0.0487}^{0.0467}{R}_J$), and brightness temperature of $2600\pm 70$ K. This object orbits with a period of 1.721553$\pm 0.000001$ days around an early M dwarf star ($0.62\pm{0.016}M_{\Sun}$). TESS photometry shows regular variations in the host star's TESS light curve, which we interpreted as activity-induced variation of $\sim$2\%, and used this variability to measure the host star's stellar rotation period of 1.9716${}_{-0.0083}^{+0.0080}$ days. The TOI-5375 system provides tight constraints on stellar models of low-mass stars at the hydrogen-burning limit and adds to the population in this important region.

15 pages, 8 figures, Accepted to the Astronomical Journal

References in corpus (22)

• The NumPy array: a structure for efficient numerical computation
• The Gaia mission
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• The Transiting Exoplanet Survey Satellite
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• Detection of Thermal Emission from an Extrasolar Planet
• Spectrum radial velocity analyser (SERVAL). High-precision radial velocities and two alternative spectral indicators
• The TESS Objects of Interest Catalog from the TESS Prime Mission
• Precision Stellar Characterization of FGKM Stars using an Empirical Spectral Library
• exoplanet: Gradient-based probabilistic inference for exoplanet data & other astronomical time series
• Correcting for Telluric Absorption: Methods, Case Studies, and Release of the TelFit Code
• On the Inference of a Star's Inclination Angle from its Rotation Velocity and Projected Rotation Velocity
• Python Leap Second Management and Implementation of Precise Barycentric Correction (barycorrpy)
• Occurrence rate of hot Jupiters around early-type M dwarfs based on TESS data
• A sub-Neptune sized planet transiting the M2.5-dwarf G 9-40: Validation with the Habitable-zone Planet Finder
• Evaluating Rotation Periods of M Dwarfs Across the Ages
• SPISEA: A Python-Based Simple Stellar Population Synthesis Code for Star Clusters
• The EBLM project III. A Saturn-size low-mass star at the hydrogen-burning limit
• TOI-3714 b and TOI-3629 b: Two gas giants transiting M dwarfs confirmed with HPF and NEID
• A warm Jupiter transiting an M dwarf: A TESS single transit event confirmed with the Habitable-zone Planet Finder
• MAROON-X: The first two years of EPRVs from Gemini North

Cited by in corpus (3)

• Searching for Giant Exoplanets around M-dwarf Stars (GEMS) I: Survey Motivation
• The GAPS programme at TNG XLIII. A massive brown dwarf orbiting the active M dwarf TOI-5375
• Spectral analysis of two directly imaged benchmark L dwarf companions at the stellar-substellar boundary