2013A&A...560A..52M


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.19CET07:27:08

2013A&A...560A..52M - Astronomy and Astrophysics, volume 560A, 52-52 (2013/12-1)

Parallax measurements of cool brown dwarfs.

MANJAVACAS E., GOLDMAN B., REFFERT S. and HENNING T.

Abstract (from CDS):

Accurate parallax measurements allow us to determine physical properties of brown dwarfs and help us constrain evolutionary and atmospheric models, break age-mass degeneracy, and reveal unresolved binaries. We measured absolute trigonometric parallaxes and proper motions of six cool brown dwarfs using background galaxies to establish an absolute reference frame. We derive the absolute J-band magnitude. The six T brown dwarfs in our sample have spectral types between T2.5 and T8 and magnitudes between 13.9 and 18.0 in the Two Micron All Sky Survey (2MASS) with photometric distances below 25pc. The observations were taken in the J-band with the Omega-2000 camera on the 3.5m telescope at Calar Alto during a time period of 27 months between March 2011 and June 2013. The number of epochs varied between 11 and 12 depending on the object. The reduction of the astrometric measurements was carried out with respect to the field stars. The relative parallax and proper motions were transformed into absolute measurements using the background galaxies in our fields. We obtained absolute parallaxes for our six brown dwarfs with a precision between 3 and 6mas. We compared our results in a color-magnitude diagram with other brown dwarfs with determined parallax and with the BT-Settl 2012 atmospheric models. For four of the six targets, we found a good agreement in luminosity with objects of similar spectral types. We obtained an improved accuracy in the parallaxes and proper motions in comparison to previous works. The object 2MASS J11061197+2754225 is more than 1mag overluminous in all bands, which point to binarity or high order multiplicity.

Abstract Copyright:

Journal keyword(s): stars: low-mass - brown dwarfs - infrared: stars - astrometry - parallaxes - proper motions

Simbad objects: 10

goto Full paper

goto View the reference in ADS

Number of rows : 10

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 2MASS J03471792+2422317 BD* 03 47 17.9128387886 +24 22 31.730547022         19.26 M8 104 0
2 2MASS J03480465+2339303 BD* 03 48 04.6589395721 +23 39 30.327153356     22.46   17.91 M6.5 96 0
3 HD 42581B BD* 06 10 34.80 -21 52 00.0           T6.5 448 0
4 2MASS J11061197+2754225 BD* 11 06 11.919 +27 54 21.58           T0.0+T4.5 19 0
5 ULAS J130217.21+130851.2 BD* 13 02 17.21 +13 08 51.2           T8.5 10 0
6 ULAS J141756.22+133045.8 Ro* 14 17 56.248 +13 30 45.57           T5.5 6 0
7 GD 165 WD* 14 24 39.1494933037 +09 17 14.161331419   14.46 14.32 14.6 14.91 DA4.1 145 0
8 2MASSI J2254188+312349 BD* 22 54 18.92 +31 23 49.8           T5.0 56 0
9 WISEP J232035.36+144830.2 BD* 23 20 35.105 +14 48 28.96           T7.0 8 0
10 WISEP J232123.83+135453.5 BD* 23 21 23.762 +13 54 58.87           T7.5 10 0

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2013A&A...560A..52M and select 'bookmark this link' or equivalent in the popup menu


2019.11.19-07:27:08

© Université de Strasbourg/CNRS

    • Contact