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+1.3 -1.0 Mjupobject separated by 1950 ±200 au (40″) from a relatively close (2.17 ±0.22 au, 0.″04) pair of 48+13 -12 Mjupand 44+14 -11 Mjupobjects. 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+0.4 -0.3 Mjup). 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.
Original language | English (US) |
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Article number | 57 |
Journal | Astronomical Journal |
Volume | 156 |
Issue number | 2 |
DOIs | |
State | Published - Aug 2018 |
Keywords
- binaries: close
- brown dwarfs
- parallaxes
- planetary systems
- stars: individual (2MASS J02495639-0557352, 2MASSW J2208136+292121)
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science