2008A&A...482..961D


Query : 2008A&A...482..961D

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 Teff∼620K and gravity of logg∼4.75. Evolutionary models translate these parameters into an age of 1-5Gyr and a mass of 15-30MJup. 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

goto Full paper

goto View the references in ADS

Number of rows : 9
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 CFBDS J003402-005206 BD* 00 34 02.77416 -00 52 06.8196           T8+/Y? 49 0
2 * 54 Psc B BD* 00 39 18.91 +21 15 16.8           T7.5 72 1
3 CFBDS J005910-011401 BD* 00 59 10.46265 -01 14 00.5404           T9.0 38 0
4 USNO-B1.0 0887-00010532 PM* 00 59 12.8351778648 -01 13 51.416392296   15.8   14.6   ~ 1 0
5 HD 13936 * 02 15 28.3109874216 -09 27 59.497762932   6.537 6.549     A0V 57 0
6 2MASSI J0415195-093506 BD* 04 15 19.54368 -09 35 06.6732           T8.0 162 0
7 HD 42581B BD* 06 10 34.80 -21 52 00.0           T6.5 496 0
8 GJ 570 D BD* 14 57 14.96256 -21 21 47.7504           T8 219 1
9 SB 935 * 23 59 42.9071780352 -37 31 50.314903500   14.2 13.810     A3 6 0

To bookmark this query, right click on this link: simbad:objects in 2008A&A...482..961D and select 'bookmark this link' or equivalent in the popup menu


2023.09.30-00:57:58

© Université de Strasbourg/CNRS

    • Contact