We present an eccentric , short-period brown dwarf candidate orbiting the active , slightly evolved subgiant star TYC 2087-00255-1 , which has effective temperature T _ { eff } = 5903 \pm 42 K , surface gravity \log ( g ) = 4.07 \pm 0.16 ( cgs ) , and metallicity [ Fe / H ] = -0.23 \pm 0.07 .
This candidate was discovered using data from the first two years of the Multi-object APO Radial Velocity Exoplanets Large-area Survey ( MARVELS ) , which is part of the third phase of Sloan Digital Sky Survey .
From our 38 radial velocity measurements spread over a two-year time baseline , we derive a Keplerian orbital fit with semi-amplitude K = 3.571 \pm 0.041 km s ^ { -1 } , period P = 9.0090 \pm 0.0004 days , and eccentricity e = 0.226 \pm 0.011 .
Adopting a mass of 1.16 \pm 0.11 M _ { \odot } for the subgiant host star , we infer that the companion has a minimum mass of 40.0 \pm 2.5 M _ { Jup } .
Assuming an edge-on orbit , the semimajor axis is 0.090 \pm 0.003 AU .
The host star is photometrically variable at the \sim 1 \% level with a period of \sim 13.16 \pm 0.01 days , indicating that the host star spin and companion orbit are not synchronized .
Through adaptive optics imaging we also found a point source 643 \pm 10 mas away from TYC 2087-00255-1 , which would have a mass of 0.13 M _ { \odot } 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 tertiary object is physically associated with TYC 2087-00255-1 and make TYC 2087-00255-1 a triple body system .
Core Ca II H and K line emission indicate that the host is chromospherically active , at a level that is consistent with the inferred spin period and measured v _ { rot } \sin i , but unusual for a subgiant of this T _ { eff } .
This activity could be explained by ongoing tidal spin-up of the host star by the companion .