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
Jiang, P; Ge, J; Cargile, P; Crepp, J. R; De Lee, N; Porto de Mello, G. F; Esposito, M.; Ferreira, L. D; Femenia, B; Fleming, S. W; Gaudi, B. S; Ghezzi, L; Gonzalez Hernandez, J. I; Hebb, L; Lee, B. L; Ma, Bo; Stassun, K. G; Wang, Ji; Wisniewski, John P; Agol, Eric; Bizyaev, Dmitry; Brewington, Howard; Chang, Liang; Nicolaci da Costa, Luiz; Eastman, Jason D; Ebelke, Garrett; Gary, Bruce; Kane, Stephen R; Li, Rui; Liu, Jian; Mahadevan, Suvrath; Maia, Marcio A. G; Malanushenko, Viktor; Malanushenko, Elena; Muna, Demitri; Nguyen, Duy Cuong; Ogando, Ricardo L. C; Oravetz, Audrey; Oravetz, Daniel; Pan, Kaike; Pepper, Joshua; Paegert, Martin; Allende Prieto, Carlos; Rebolo, Rafael; Santiago, Basilio X; Schneider, Donald P; Shelden Bradley, Alaina C; Sivarani, T; Snedden, Stephanie; van Eyken, J. C; Wan, Xiaoke; Weaver, Benjamin A; Zhao, Bo
Date:
2013-09
Abstract:
We report the discovery of a candidate brown dwarf (BD) or a very low mass stellar companion (MARVELS-5b) to the star HIP 67526 from the Multi-object Apache point observatory Radial Velocity Exoplanet Large-area Survey (MARVELS). The radial velocity curve for this object contains 31 epochs spread over 2.5 yr. Our Keplerian fit, using a Markov Chain Monte Carlo approach, reveals that the companion has an orbital period of $90.2695^{+0.0188}_{-0.0187}$ days, an eccentricity of 0.4375 ± 0.0040, and a semi-amplitude of $2948.14^{+16.65}_{-16.55}$ m s–1. Using additional high-resolution spectroscopy, we find the host star has an effective temperature T eff = 6004 ± 34 K, a surface gravity log g (cgs) =4.55 ± 0.17, and a metallicity [Fe/H] =+0.04 ± 0.06. The stellar mass and radius determined through the empirical relationship of Torres et al. yields 1.10 ± 0.09 M ☉ and 0.92 ± 0.19 R ☉. The minimum mass of MARVELS-5b is 65.0 ± 2.9M Jup, indicating that it is likely to be either a BD 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 ± 10 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 0.2 M ☉ at a separation larger than 40 AU.
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