A Jupiter Analog Orbiting The Nearby M Dwarf GJ 463

Abstract

We report the detection of a long-period giant planetary companion to the nearby M3V star GJ 463 (=Ross 690). The detection is based on over ten years of highly-precise radial velocity measurements with the High Resolution Spectrograph at the Hobby–Eberly Telescope and the HIRES spectrograph at Keck. With an orbital period of 10 yr and a minimum mass of 1.55 ± 0.15 M _Jup, GJ 463 b has a comparable orbital period to Jupiter and hence qualifies as a Jupiter analog around a low-mass star. We demonstrate that the radial velocity signal is not produced by a magnetic activity cycle of the host star. GJ 463 was observed with TESS, and we searched the light curve for any possible signals of stellar or planetary origin, but detected none. This planet is a candidate for possible direct detection with the coronagraph of the upcoming Nancy Grace Roman Space Telescope. We compared Gaia EDR3 with Hipparcos astrometry and detected a significant acceleration, which is likely caused by this long-period planetary companion at a = 3.53 ± 0.07 au.