2008A&A...481..757B


C.D.S. - SIMBAD4 rel 1.7 - 2021.01.24CET01:58:52

2008A&A...481..757B - Astronomy and Astrophysics, volume 481, 757-767 (2008/4-3)

Follow-up observations of binary ultra-cool dwarfs.

BOUY H., MARTIN E.L., BRANDNER W., FORVEILLE T., DELFOSSE X., HUELAMO N., BASRI G., GIRARD J., ZAPATERO OSORIO M.-R., STUMPF M., GHEZ A., VALDIVIELSO L., MARCHIS F., BURGASSER A.J. and CRUZ K.

Abstract (from CDS):

Astrometric observations of resolved binaries provide estimates of orbital periods and will eventually lead to measurement of dynamical masses. Only a few very low mass star and brown dwarf masses have been measured to date, and the mass-luminosity relation still needs to be calibrated. We have monitored 14 very low mass multiple systems for several years to confirm their multiplicity and, for those with a short period, derive accurate orbital parameters and dynamical mass estimates. We have used high spatial resolution images obtained at the Paranal, Lick and HST observatories to obtain astrometric and photometric measurements of the multiple systems at several epochs. The targets have periods ranging from 5 to 200 years, and spectral types in the range M7.5-T5.5. All of our 14 multiple systems are confirmed as common proper motion pairs. One system (2MASSW J0920122+351742) is not resolved in our new images, probably because the discovery images were taken near maximum elongation. Six systems have periods short enough to allow dynamical mass measurements within the next 15 to 20 years. We estimate that only 8% of the ultracool dwarfs in the solar neighborhood are binaries with separations large enough to be resolved, and yet periods short enough to derive astrometric orbital fits over a reasonable time frame with current instrumentation. A survey that doubles the number of ultracool dwarfs observed with high angular resolution is called for to discover enough binaries for a first attempt to derive the mass-luminosity relationship for very low-mass stars and brown dwarfs.

Abstract Copyright:

Journal keyword(s): stars: low-mass, brown dwarfs - binaries: visual - techniques: high angular resolution

Simbad objects: 19

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Number of rows : 19

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 L 362-29 B BD* 00 04 34.8641153471 -40 44 06.464450691       19.61 16.88 L5+L5 95 0
2 2MASS J03572695-4417305 BD* 03 57 26.9620991711 -44 17 30.499748423         17.86 L0beta 29 0
3 2MASS J08503593+1057156 BD* 08 50 35.93400 +10 57 15.6168       22.466 20.349 L6.5+L8.5 69 0
4 UCAC2 44134528 * 09 20 10.9361527652 +35 17 45.341873130       12.19   ~ 1 0
5 2MASSW J0920122+351742 BD* 09 20 12.23664 +35 17 42.9684           L5.5+L9 42 0
6 2MASS J10042824-1146489 ** 10 04 28.2256458705 -11 46 49.015314646         18.021 ~ 6 2
7 LP 213-67 PM* 10 47 12.6093653326 +40 26 43.728916506   19.2       M6.5Ve 34 1
8 LP 213-68 ** 10 47 13.7773543561 +40 26 49.271483418   21.2   19.1   M8+L0 31 0
9 2MASS J11463449+2230527 BD* 11 46 34.49088 +22 30 52.7400           L3+L4 82 0
10 2MASSI J1311391+803222 ** 13 11 39.2408171510 +80 32 21.912329971   21.4   18.6   M7.5+M8 14 0
11 2MASSI J1426316+155701 LM* 14 26 31.6111849008 +15 57 01.045067058       18.320 15.819 M9V 27 0
12 DENIS J144137.2-094558 BD* 14 41 37.1670168475 -09 45 59.155474431       20.030 17.234 L1+L1 48 0
13 2MASSI J1534498-295227 BD* 15 34 49.84080 -29 52 27.4188           T4.5+T5 59 0
14 2MASSW J1728114+394859 BD* 17 28 11.50056 +39 48 59.3100           L5+L6.5 52 0
15 USNO-B1.0 1453-00276611 * 18 47 00.5668740474 +55 22 26.152826002   16.7   15.0   ~ 1 0
16 2MASSI J1847034+552243 SB* 18 47 03.43152 +55 22 43.5216   18.7   16.4   M6+M7 12 0
17 2MASS J21402931+1625183 ** 21 40 29.3210817966 +16 25 18.154294077         15.36 M8+M9.5 25 0
18 * eps Ind B BD* 22 04 10.52064 -56 46 57.7452     24.12 20.8 15.60 T1V+T6V 134 2
19 2MASSW J2331016-040618 ** 23 31 01.6274111105 -04 06 19.514168805       19.2 15.51 M8.0V+L3.0V 24 0

    Equat.    Gal    SGal    Ecl

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