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We present an eccentric, short-period brown dwarf candidate orbiting theactive, slightly evolved subgiant star TYC 2087-00255-1, which has effectivetemperature T_eff = 5903+/-42 K, surface gravity log (g) = 4.07+/-0.16 (cgs),and metallicity [Fe/H] = -0.23+/-0.07. This candidate was discovered using datafrom the first two years of the Multi-object APO Radial Velocity ExoplanetsLarge-area Survey (MARVELS), which is part of the third phase of Sloan DigitalSky Survey. From our 38 radial velocity measurements spread over a two-yeartime baseline, we derive a Keplerian orbital fit with semi-amplitudeK=3.571+/-0.041 km/s, period P=9.0090+/-0.0004 days, and eccentricitye=0.226+/-0.011. Adopting a mass of 1.16+/-0.11 Msun for the subgiant hoststar, we infer that the companion has a minimum mass of 40.0+/-2.5 M_Jup.Assuming an edge-on orbit, the semimajor axis is 0.090+/-0.003 AU. The hoststar is photometrically variable at the \sim1% level with a period of\sim13.16+/-0.01 days, indicating that the host star spin and companion orbitare not synchronized. Through adaptive optics imaging we also found a pointsource 643+/-10 mas away from TYC 2087-00255-1, which would have a mass of 0.13Msun if it is physically associated with TYC 2087-00255-1 and has the same age.Future proper motion observation should be able to resolve if this tertiaryobject is physically associated with TYC 2087-00255-1 and make TYC 2087-00255-1a triple body system. Core Ca II H and K line emission indicate that the hostis chromospherically active, at a level that is consistent with the inferredspin period and measured v_{rot}*sin i, but unusual for a subgiant of thisT_eff. This activity could be explained by ongoing tidal spin-up of the hoststar by the companion.

the astronomical journal

Very Low-mass Stellar and Substellar Companions to Solar-like Stars from  Marvels III: A Short-Period Brown Dwarf Candidate Around An Active G0Iv  Subgiant