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

Trent J. Dupuy, Michael C. Liu, Katelyn N. Allers, Beth A. Biller, Kaitlin M. Kratter, Andrew W. Mann, Evgenya Shkolnik, Adam L. Kraus, William M.J. Best

Research output: Contribution to journalArticle

12 Scopus citations

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 languageEnglish (US)
Article number57
JournalAstronomical Journal
Volume156
Issue number2
DOIs
StatePublished - 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

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