The Hawaii Infrared Parallax Program. III. 2MASS J0249–0557 c: A Wide Planetary-mass Companion to a Low-mass Binary in the β Pic Moving Group* ^†

Abstract

We have discovered a wide planetary-mass companion to the βPic moving group member 2MASSJ02495639 −0557352 (M6 VL-G) using Canada-France-Hawaii Telescope/WIRCam astrometry from the Hawaii Infrared Parallax Program. In addition, Keck laser guide star adaptive optics aperture-masking interferometry shows that the host is itself a tight binary. Altogether, 2MASSJ0249−0557ABc is a bound triple system with an 11.6 1.0 1.3-+ M Jup object separated by 1950±200 au (40″) from a relatively close (2.17±0.22 au, 0 04) pair of 48 12 13-+ M Jup and 44 11 14-+ M Jup objects. 2MASSJ0249−0557AB is one of the few ultracool binaries to be discovered in a young moving group and the first confirmed in the βPic moving group (22±6 Myr). The mass, absolute magnitudes, and spectral type of 2MASSJ0249−0557c (L2 VL-G) are remarkably similar to those of the planet βPicb (L2, 13.0 0.3 0.4-+ M Jup). We also find that the free-floating object 2MASSJ2208+2921 (L3 VL-G) is another possible βPic moving group member with colors and absolute magnitudes similar to βPicb and 2MASSJ0249−0557c. βPicb is the first directly imaged planet to have a "twin," namely an object of comparable properties in the same stellar association. Such directly imaged objects provide a unique opportunity to measure atmospheric composition, variability, and rotation across different pathways of assembling planetary-mass objects from the same natal material.

Strong H$α$ emission in the young planetary mass companion 2MASS J0249-0557 c

“…We observe a tentative Li I detection with a pEW of 5 Å. These features are consistent with the very low gravity classification by Dupuy et al (2018) and with the expected membership in β Pic.…”

“…panion of the binary brown dwarfs 2MASS J0249−0557 AB, recently discovered by Dupuy et al (2018). We found this candidate companion in our proper motion search around YMG members by combining the astrometry and photometry of the VHS and 2MASS catalogues, and using photometry from other catalogues such as DENIS and/or AllWise, and astrometry from Gaia DR2, when available.…”

An eclipsing substellar binary in a young triple system discovered by SPECULOOS

“…The parameters shown are the period P (in days), the time of eclipse (in heliocentric Julidan data JD -2450000), the cosine of inclination i, the factors √e sin ω and √e cos ω where e is eccentricity and ω the argument of periapsis, the sum of the fractional component radii (r1+r2 = (R1+R2)/a), the primary velocity amplitude, the secondary velocity amplitude, and velocity offsets (including systemic motion) for NIRSPEC (γNIRSPEC) and UVES (γUVES) observations. Supplementary Fully resolved [89]…”

The Hawaii Infrared Parallax Program. V. New T-Dwarf Members and Candidate Members of Nearby Young Moving Groups

“…A plethora of planetary-mass objects have been discovered beyond our solar system in the past 25 years. Among these objects, gas-giant planets (≈ 1 − 13 M Jup ) that are either wide-separation companions to stars or brown dwarfs (e.g., Goldman et al 2010;Naud et al 2014;Miles-Páez et al 2017;Dupuy et al 2018) or free-floating objects (e.g., Liu et al 2013;Best et al 2017;Schneider et al 2017;Zhang et al 2018) are a valuable subset for high-quality emission spectroscopy, given the lack of the contaminating light from host stars. These objects thereby serve as excellent laboratories to study self-luminous exoplanet atmospheres, as well as exoplanet formation and evolution.…”