2008A&A...482..961D -
Astronomy and Astrophysics, volume 482, 961-971 (2008/5-2)
CFBDS J005910.90-011401.3: reaching the T-Y brown dwarf transition?
DELORME P., DELFOSSE X., ALBERT L., ARTIGAU E., FORVEILLE T., REYLE C., ALLARD F., HOMEIER D., ROBIN A.C., WILLOTT C.J., LIU M.C. and DUPUY T.J.
Abstract (from CDS):
We report the discovery of
CFBDS J005910.90-011401.3 (hereafter
CFBDS0059), the coolest brown dwarf identified to date. We found
CFBDS0059 using i' and z' images from the Canada-France-Hawaii Telescope (CFHT), and present optical and near-infrared photometry, Keck laser-guide-star adaptive optics imaging, and a complete near-infrared spectrum, from 1.0 to 2.2µm. A side-to-side comparison of the near-infrared spectra of
CFBDS0059 and
ULAS J003402.77-005206.7 (hereafter
ULAS0034), previously the coolest known brown dwarf, indicates that
CFBDS0059 is ∼50±15K cooler. We estimate a temperature of T
eff∼620K and gravity of logg∼4.75. Evolutionary models translate these parameters into an age of 1-5Gyr and a mass of 15-30M
Jup. We estimate a photometric distance of ∼13pc, which puts
CFBDS0059 within easy reach of accurate parallax measurements. Its large proper motion suggests membership in the older population of the thin disk. The spectra of both
CFBDS0059 and ULAS J0034 show probable absorption by a wide ammonia band on the blue side of the H-band flux peak. If, as we expect, that feature deepens further for still lower effective temperatures, its appearance will become a natural breakpoint for the transition between the T spectral class and the new Y spectral type. Together,
CFBDS0059 and ULAS J0034 would then be the first Y0 dwarfs.
Abstract Copyright:
∼
Journal keyword(s):
techniques: spectroscopic - surveys - stars: atmospheres - infrared: stars - stars: low-mass, brown dwarfs
Nomenclature:
Text: CFBDS JHHMMSS.ss+DDMMSS.s N=2 = CFBDS JHHMMSS+DDMMSS N=2.
Simbad objects:
9
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2008A&A...482..961D and select 'bookmark this link' or equivalent in the popup menu