2004A&A...423..341B


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.14CEST02:31:51

2004A&A...423..341B - Astronomy and Astrophysics, volume 423, 341-352 (2004/8-3)

First determination of the dynamical mass of a binary L dwarf.

BOUY H., DUCHENE G., KOEHLER R., BRANDNER W., BOUVIER J., MARTIN E.L., GHEZ A., DELFOSSE X., FORVEILLE T., ALLARD F., BARAFFE I., BASRI G., CLOSE L. and McCABE C.E.

Abstract (from CDS):

We present here the results of astrometric, photometric and spectroscopic observations leading to the determination of the orbit and dynamical masses of the binary L dwarf 2MASSW J0746425+2000321. High angular resolution observations spread over almost 4 years and obtained with the Hubble Space Telescope (HST), the ESO Very Large Telescope (VLT), and a the W. M. Keck Observatory (Keck) allow us to cover ∼36% of the period, corresponding to 60% of the orbit, and, for the first time, to derive a precise estimate of the total and individual masses of such a late-type object. We find an orbital period of 3850.9+904–767days. The corresponding total mass is 0.146+0.016–0.006M with uncertainties depending on the distance. Spatially resolved low resolution optical (550-1025nm) spectra have been obtained with HST/STIS, allowing us to measure the spectral types of the two components (L0±0.5 for the primary and L1.5±0.5 for the secondary). We also present precise photometry of the individual components measured on the high angular resolution images obtained with HST/ACS and WFPC2 (visible), VLT/NACO (J, H and KS bands) and Keck I (KS band). These spectral and photometric measurements enable us to estimate their effective temperatures and mass ratio, and to place the object accurately in a H-R diagram. The binary system is most likely formed by a primary with a mass of 0.085±0.010M and a secondary with a mass of 0.066±0.006M, thus clearly substellar, for an age of approximately 300±150Myr. Hα variability indicates chromospheric and/or magnetic activity.

Abstract Copyright:

Journal keyword(s): stars: low-mass, brown dwarfs - star: individual: 2MASSW J0746425+2000321 - stars: binary (including multiple): close - techniques: high angular resolution - stars: binaries: visual

Simbad objects: 8

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Number of rows : 8

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 DENIS J0243.8-5432 LM* 02 43 51.0507360706 -54 32 19.364765354         17.05 M9 7 0
2 LSPM J0746+2000 BD* 07 46 42.49536 +20 00 32.6124       17.9 15.034 L0+L1.5 170 1
3 DENIS J090957.1-065806 BD* 09 09 57.4817507796 -06 58 18.650158294     19.2     L0.2V 33 0
4 V* BX Ant TT* 10 18 28.6989165716 -31 50 02.826261802   13.39 11.454 11.382 9.325 M0Ve 103 0
5 NAME Kelu-1 BD* 13 05 40.1737206066 -25 41 05.830344467         16.85 L2+L3.5 236 0
6 2MASS J13150088-2513015 PM* 13 15 00.8837707587 -25 13 01.690177854           M8: 2 0
7 G 124-62B BD* 14 41 37.1670168475 -09 45 59.155474431       20.030 17.234 L1+L1 48 0
8 BD+16 2708B SB* 14 54 29.4185719182 +16 06 08.616294953           M8.5 130 0

    Equat.    Gal    SGal    Ecl

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2020.08.14-02:31:51

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