We report the detections of a giant planet ( MARVELS-7b ) and a brown dwarf candidate ( MARVELS-7c ) around the primary star in the close binary system , HD 87646 .
It is the first close binary system with more than one substellar circum-primary companion discovered to the best of our knowledge .
The detection of this giant planet was accomplished using the first multi-object Doppler instrument ( KeckET ) at the Sloan Digital Sky Survey ( SDSS ) telescope .
Subsequent radial velocity observations using ET at Kitt Peak National Observatory , HRS at HET , the “ Classic ” spectrograph at the Automatic Spectroscopic Telescope at Fairborn Observatory , and MARVELS from SDSS-III confirmed this giant planet discovery and revealed the existence of a long-period brown dwarf in this binary .
HD 87646 is a close binary with a separation of \sim 22 AU between the two stars , estimated using the Hipparcos catalogue and our newly acquired AO image from PALAO on the 200-inch Hale Telescope at Palomar .
The primary star in the binary , HD 87646A , has T _ { eff } = 5770 \pm 80K , log g =4.1 \pm 0.1 and [ Fe/H ] = -0.17 \pm 0.08 .
The derived minimum masses of the two substellar companions of HD 87646A are 12.4 \pm 0.7 M _ { Jup } and 57.0 \pm 3.7 M _ { Jup } .
The periods are 13.481 \pm 0.001 days and 674 \pm 4 days and the measured eccentricities are 0.05 \pm 0.02 and 0.50 \pm 0.02 respectively .
Our dynamical simulations show the system is stable if the binary orbit has a large semi-major axis and a low eccentricity , which can be verified with future astrometry observations .