The widest ultracool binary

Abstract

Aims: I test the ejection scenario of formation of brown dwarfs and very low-mass stars through the detection of a very wide ultracool binary. Methods: LEHPM 494 (M6.0 +/- 1.0 V) and DENIS-P J0021.0-4244 (M9.5 +/- 0.5 V) are separated by 1.3 arcmin and are high proper motion co-moving ultracool stars. I have used six astrometric epochs spaced 22 years to confirm their common tangential velocity. Results: The angular separation between both low-mass stars keeps constant with an uncertainty less than 0.1 %. I have also derived their most probable heliocentric distance (23 +/- 2 pc), age interval (2-10 Ga) and masses (0.103 +/- 0.006 and 0.079 +/- 0.004 Msol). The pair, with a projected physical separation of 1800 +/- 170 AU, is by far the widest ultracool binary ever found in the field. Conclusions: This serendipitous and simple detection is inconsistent with ultra low-mass formation ejection scenarios and complements current searches of low-mass tight binaries.

Submitted to A&A Letters on Nov 26. Comments by referee already introduced

References in corpus (25)

• The USNO-B Catalog
• Evolutionary models for very-low-mass stars and brown dwarfs with dusty atmospheres
• A Giant Planet Candidate near a Young Brown Dwarf
• Astrometry and Photometry for Cool Dwarfs and Brown Dwarfs
• The SuperCOSMOS Sky Survey. Paper I: Introduction and Description
• Rotation and Activity in Mid-M to L Dwarfs
• Preliminary Parallaxes of 40 L and T Dwarfs from the U.S. Naval Observatory Infrared Astrometry Program
• Binarity in Brown Dwarfs: T Dwarf Binaries Discovered with the Hubble Space Telescope WPFC2
• The Formation Mechanism of Brown Dwarfs
• An Effective Temperature Scale for Late M and L Dwarfs, from Resonance Absorption Lines of CsI and RbI
• Discovery of a Low-Mass Brown Dwarf Companion of the Young Nearby Star G196-3
• A Survey for Spectroscopic Binaries Among Very Low-Mass Stars
• Multiplicity Amongst Wide Brown Dwarf Companions to Nearby Stars: Gliese 337CD
• The First Discovery of a Wide Binary Brown Dwarf
• Resolved Spectroscopy of M Dwarf/L Dwarf Binaries. I. DENIS J220002.05-303832.9AB
• The dependence of the sub-stellar IMF on the initial conditions for star formation
• The Decay of Accreting Triple Systems as Brown Dwarf Formation Scenario
• The brown dwarf population in the Chamaeleon I cloud
• Multiplicity of very low-mass objects in the Upper Scorpius OB association: a possible wide binary population
• The Liverpool-Edinburgh High Proper Motion Survey
• The first wide ultracool binary dwarf in the field: DENIS-J055146.0-443412.2 (M8.5 + L0)
• Very low-mass members of the Lupus 3 cloud
• The dM4.5e star G124-62 and its binary L dwarf companion DENIS-P J1441-0945: Common proper motion, distance, age, and masses
• Discovery of a widely separated binary system of very low mass stars
• Discovery of a Wide Low-mass Binary System in Upper Scorpius

Cited by in corpus (33)

• Stellar Multiplicity
• The Hawaii Infrared Parallax Program. I. Ultracool Binaries and the L/T Transition
• The Solar Neighborhood XXXII. The Hydrogen Burning Limit
• On the evolution of a star cluster and its multiple stellar systems following gas dispersal
• Unusually Wide Binaries: Are They Wide or Unusual?
• Discovery of a Wide Binary Brown Dwarf Born in Isolation
• Multiple Star Formation to the Bottom of the IMF
• Reaching the boundary between stellar kinematic groups and very wide binaries. The Washington Double Stars with the widest angular separations
• Southern wide very low-mass stars and brown dwarfs in resolved binary and multiple systems
• The High-Order-Multiplicity of Unusually Wide M-dwarf Binaries: Eleven New Triple and Quadruple Systems
• Multiplicity Among Young Brown Dwarfs and Very Low Mass Stars
• The LuckyCam Survey for Very Low Mass Binaries II: 13 new M4.5-M6.0 Binaries
• Reaching the boundary between stellar kinematic groups and very wide binaries. III. Sixteen new stars and eight new wide systems in the beta Pictoris moving group
• Discovery of the Widest Very Low Mass Binary
• Discovery of a Very Low Mass Triple with Late-M and T Dwarf Components: LP 704-48/SDSS J0006-0852AB
• The Hercules-Lyra Association revisited New age estimation and multiplicity study
• Discovery of the Widest Very Low Mass Field Binary
• Young stars and brown dwarfs surrounding Alnilam (eps Ori) and Mintaka (del Ori)
• Shaping the Brown Dwarf Desert: Predicting the Primordial Brown Dwarf Binary Distributions from Turbulent Fragmentation
• The dynamical evolution of very-low mass binaries in open clusters
• A search for southern ultracool dwarfs in young moving groups
• Binarity at the L/T brown dwarf transition
• Was Proxima captured by alpha Centauri A and B?
• Resolved Spectroscopy of M Dwarf/L Dwarf Binaries. III. The "Wide" L3.5/L4 Dwarf Binary 2MASS J15500845+1455180AB
• The young, wide and very low mass visual binary LOri167
• Discovery of wide low and very low-mass binary systems using Virtual Observatory tools
• Multiplicity of stars with planets in the solar neighbourhood
• On the Age of the Widest Very Low Mass Binary
• Reaching the boundary between stellar kinematic groups and very wide binaries. IV. The widest Washington double star systems with rho > 1000 arcsec in Gaia DR3
• The magnetically-active, low-mass, triple system WDS 19312+3607
• One is the loneliest number: multiplicity in cool dwarfs
• The Brown Dwarf Kinematics Project (BDKP). II. Details on Nine Wide Common Proper Motion Very Low-Mass Companions to Nearby Stars
• Detection and characterisation of two VLM binaries: LP 1033-31 and LP 877-72