Discovery And Characterization of Wide Binary Systems With a Very Low Mass Component

Abstract

We report the discovery of 14 low-mass binary systems containing mid-M to mid-L dwarf companions with separations larger than 250 AU. We also report the independent discovery of 9 other systems with similar characteristics that were recently discovered in other studies. We have identified these systems by searching for common proper motion sources in the vicinity of known high proper motion stars, based on a cross-correlation of wide area near-infrared surveys (2MASS, SDSS, and SIMP). An astrometric follow-up, for common proper motion confirmation, was made with SIMON and/or CPAPIR at the OMM 1.6 m and CTIO 1.5 m telescopes for all the candidates identified. A spectroscopic follow-up was also made with GMOS or GNIRS at Gemini to determine the spectral types of 11 of our newly identified companions and 10 of our primaries. Statistical arguments are provided to show that all of the systems we report here are very likely to be physical binaries. One of the new systems reported features a brown dwarf companion: LSPM J1259+1001 (M5) has an L4.5 (2M1259+1001) companion at about 340 AU. This brown dwarf was previously unknown. Seven other systems have a companion of spectral type L0-L1 at a separation in the 250-7500 AU range. Our sample includes 14 systems with a mass ratio below 0.3.

18 pages, 6 figures

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• A Brown Dwarf Census from the SIMP Survey
• An ablating super-Earth in an eccentric binary from the Dispersed Matter Planet Project
• Spectroscopic binaries in the Solar Twin Planet Search program: from substellar-mass to M dwarf companions
• Ultracool dwarf benchmarks with \emph{Gaia} primaries
• Discovery of wide low and very low-mass binary systems using Virtual Observatory tools
• The $\text{Gaia}$ Ultra-Cool Dwarf Sample $-$ III: Seven new multiple systems containing at least one $\text{Gaia}$ DR2 ultra-cool dwarf
• A low-mass triple system with a wide L/T transition brown dwarf component: NLTT 51469AB/SDSS 2131-0119
• Detection and characterisation of two VLM binaries: LP 1033-31 and LP 877-72