Discovery of the Brightest T Dwarf in the Northern Hemisphere

Abstract

We report the discovery of a bright (H = 12.77) brown dwarf designated SIMP J013656.5+093347. The discovery was made as part of a near-infrared proper motion survey, SIMP (Sondage Infrarouge de Mouvement Propre), which uses proper motion and near-infrared/optical photometry to identify brown dwarf candidates. A low resolution (λ/∆λ ∼ 40) spectrum of this brown dwarf covering the 0.88-2.35 µm wavelength interval is presented. Analysis of the spectrum indicates a spectral type of T2.5 ± 0.5. A photometric distance of 6.4 ± 0.3 pc is estimated assuming it is a single object. Current observations rule out a binary of mass ratio ∼1 and separation 5 AU. SIMP 0136 is the brightest T dwarf in the northern hemisphere and is surpassed only by ε Indi Bab over the whole sky. It is thus an excellent candidate for detailed studies and should become a benchmark object for the early-T spectral class.

The brown dwarf atmosphere monitoring (BAM) project

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A Brown Dwarf Census From the Simp Survey

“…One object, J0136+0933 was discovered previously as part of the SIMP survey by Artigau et al (2006). This paper presents an unpublished GNIRS spectrum.…”

“…This survey has already enabled the discovery of several UCDs: a bright, nearby T2.5 dwarf (SIMP J013656.5+093347; Artigau et al 2006), five very low-mass binaries (SIMP J1619275+031350AB & SIMP J1501530−013506AB; Artigau et al 2011, an I − J color is calculated using the SSS survey limit, I = 19.5. For the UCDs discovered in this work and other known UCDs, the i-band magnitude was obtained from SDSS or Megacam when available.…”

ON THE RADII OF BROWN DWARFS MEASURED WITHAKARINEAR-INFRARED SPECTROSCOPY

“…The D of each object has been calculated from its parallax given in the fourth column of Table 1, except for SIMP J0136+0933 for which the value is a spectrophotometric estimate. The distance of SIMP J0136+0933 is estimated by comparing the flux with known brown dwarfs of similar spectral types (Artigau et al 2006). The model flux F ν is from the UCM best-fit model spectra given by Sorahana & Yamamura (2012).…”