2001A&A...365..514G


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.23CEST02:11:30

2001A&A...365..514G - Astronomy and Astrophysics, volume 365, 514-518 (2001/1-3)

Infrared spectrum and proper motion of the brown dwarf companion of HR 7329 in Tucanae.

GUENTHER E.W., NEUHAEUSER R., HUELAMO N., BRANDNER W. and ALVES J.

Abstract (from CDS):

Up to now only four brown dwarf companions to normal stars have been found and confirmed by both spectroscopy and proper motion (namely Gl 229B, G 196-3B, Gl 570D, and CoD-33 ° 7795B). On the basis of an optical spectrum taken with HST/STIS Lowrance et al. (2000ApJ...541..390L) recently pointed out another possible candidate companion. The companion candidate is located at a distance of 4'' from the A0-star HR 7329, which is considered as a member of a moving group of young stars in Tucanae located at a distance of only ∼48pc. In order to confirm or disregard the companion nature of the candidate, we have determined the proper motion of the brown dwarf candidate with an epoch difference of 1.8 years, and found that it is consistent with a co-moving companion of HR 7329. Additional to the proper motion measurement, we have also taken an H-band spectrum using ISAAC on the ESO-VLT. From this spectrum, we conclude that the companion candidate has spectral type M 7 to M 8, which is in agreement with the optical spectrum. We thus conclude that HR 7329B is most likely a brown dwarf companion. The mass ratio of this pair (A0 to M 7-8, i.e. ∼100:1) is the largest known among brown dwarf companions, which is relevant for studying the formation of brown dwarfs as companions.

Abstract Copyright:

Journal keyword(s): stars: binaries: visual - individual: HR 7329 - late-type - pre-main sequence

CDS comments: Companion of HR 7329 is HD 181296 B

Simbad objects: 16

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Number of rows : 16

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 NAME Horologium Association As* 02 10.0 -54 30           ~ 51 0
2 * iot Hor PM* 02 42 33.4664838826 -50 48 01.056222150   5.97 5.40     F8V 343 1
3 Cl Melotte 22 OpC 03 47 00 +24 07.0           ~ 3023 0
4 [RRN96] GG Tau Bb TT* 04 32 30.28224 +17 31 30.3024           M6+M7.5 76 1
5 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 3542 0
6 HD 42581B BD* 06 10 34.80 -21 52 00.0           T6.5 463 0
7 G 196-3B BD* 10 04 20.6389184345 +50 22 59.448807780           L3beta 91 0
8 G 196-3 Ro* 10 04 21.4628959388 +50 23 13.387216700       11.323   M3.0V 70 0
9 NAME TW Hya Association As* 11 01.9 -34 42           ~ 826 0
10 NAME Cha I MoC 11 06 48 -77 18.0           ~ 985 1
11 CD-33 7795B LM* 11 31 55.2500 -34 36 25.200     20.40   15.8 M8.5/9e 118 0
12 GJ 570 D BD* 14 57 14.96256 -21 21 47.7504           T8 195 1
13 * eta Tel PM* 19 22 51.2064652963 -54 25 26.152538950   5.035 5.020   4.99 A0V+M7/8V 190 0
14 * eta Tel B LM* 19 22 51.26 -54 25 30.7           M7.5V 65 0
15 HD 188112 HS* 19 54 31.4192112333 -28 20 20.679022097   10.01 10.22     sdB 79 0
16 NAME Tuc Galaxy G 22 41 49.6 -64 25 10   15.7 15.2     ~ 268 0

    Equat.    Gal    SGal    Ecl

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2020.10.23-02:11:30

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