HIP 33609 b: An Eccentric Brown Dwarf Transiting a V = 7.3 Rapidly Rotating B Star
Abstract
We present the discovery and characterization of HIP 33609 b, a transiting warm brown dwarf orbiting a late B star, discovered by NASA's Transiting Exoplanet Survey Satellite as TOI-588 b. HIP 33609 b is a large (R b = ${1.580}_{-0.070}^{+0.074}$ R J) brown dwarf on a highly eccentric (e = ${0.560}_{-0.031}^{+0.029}$ ) orbit with a 39 days period. The host star is a bright (V = 7.3 mag), T eff = 10,400 ${}_{-660}^{+800}$ K star with a mass of M * = ${2.383}_{-0.095}^{+0.10}$ M ⊙ and radius of R * = ${1.863}_{-0.082}^{+0.087}$ R ⊙, making it the hottest transiting brown dwarf host star discovered to date. We obtained radial velocity measurements from the CHIRON spectrograph confirming the companion's mass of M b = ${68.0}_{-7.1}^{+7.4}$ M J as well as the host star's rotation rate ( $v\sin {i}_{* }=55.6\pm 1.8$ km s-1). We also present the discovery of a new comoving group of stars, designated as MELANGE-6, and determine that HIP 33609 is a member. We use a combination of rotation periods and isochrone models fit to the cluster members to estimate an age of 150 ± 25 Myr. With a measured mass, radius, and age, HIP 33609 b becomes a benchmark for substellar evolutionary models.
- Publication:
-
The Astronomical Journal
- Pub Date:
- June 2023
- DOI:
- 10.3847/1538-3881/acd197
- arXiv:
- arXiv:2301.09663
- Bibcode:
- 2023AJ....165..268V
- Keywords:
-
- Exoplanets;
- Brown dwarfs;
- Young star clusters;
- Direct imaging;
- CCD photometry;
- High resolution spectroscopy;
- Exoplanet evolution;
- 498;
- 185;
- 1833;
- 387;
- 208;
- 2096;
- 491;
- Astrophysics - Earth and Planetary Astrophysics;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 16 pages, 5 figures, 4 tables, Submitted to AAS Journals