Very Low Mass Stellar and Substellar Companions to Solar-like Stars From MARVELS IV: A Candidate Brown Dwarf or Low-Mass Stellar Companion to HIP 67526

Jul 11, 2013
35 pages
Published in:
  • Astron.J. 146 (2013) 65
e-Print:

Citations per year

0 Citations
Abstract: (arXiv)
We report the discovery of a candidate brown dwarf or a very low mass stellar companion (MARVELS-5b) to the star HIP 67526 from the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS). The radial velocity curve for this object contains 31 epochs spread over 2.5 years. Our Keplerian fit using a Markov Chain Monte Carlo approach, reveals that the companion has an orbital period of 90.26950.0187+0.018890.2695^{+0.0188}_{-0.0187} days, an eccentricity of 0.4375±0.00400.4375 \pm 0.0040 and a semi-amplitude of 2948.1416.55+16.652948.14^{+16.65}_{-16.55} m s1^{-1}. Using additional high-resolution spectroscopy, we find the host star has an effective temperature Teff=6004±34T_{\rm{eff}}=6004 \pm 34 K, a surface gravity logg\log g [cgs] =4.55±0.17=4.55 \pm 0.17 and a metallicity [Fe/H] =+0.04±0.06=+0.04 \pm 0.06. The stellar mass and radius determined through the empirical relationship of Torres et al. (2010), yields 1.10±\pm0.09 M_{\sun} and 0.92±\pm0.19 R_{\sun}. The minimum mass of MARVELS-5b is 65.0±2.9MJup65.0 \pm 2.9 M_{Jup}, indicating that it is likely to be either a brown dwarf or a very low mass star, thus occupying a relatively sparsely-populated region of the mass function of companions to solar-type stars. The distance to this system is 101±\pm10 pc from the astrometric measurements of Hipparcos. No stellar tertiary is detected in the high-contrast images taken by either FastCam lucky imaging or Keck adaptive optics imaging, ruling out any star with mass greater than 0.2M_{\sun} at a separation larger than 40 AU.
Note:
  • 35 Pages, 10 Figures, 4 Tables, Accepted for Publication in The Astronomical Journal