2000A&A...360L..39N


C.D.S. - SIMBAD4 rel 1.7 - 2020.10.21CEST15:09:04

2000A&A...360L..39N - Astronomy and Astrophysics, volume 360, L39-42 (2000/8-3)

Spectrum and proper motion of a brown dwarf companion of the T Tauri star CoD-33 ° 7795.

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

Abstract (from CDS):

We present optical and infrared spectra as well as the proper motion of an H=12mag object 2'' off the ∼5mag brighter spectroscopic binary star CoD-33 ° 7795 (=TWA-5), a member of the TW Hya association of T Tauri stars at ∼55pc. It was suggested as companion candidate by Lowrance et al. (1999ApJ...512L..69L) and Webb et al. (1999ApJ...512L..63W), but neither a spectrum nor the proper motion of the faint object were available before. Our spectra taken with FORS2 and ISAAC at the ESO-VLT reveal that the companion candidate has spectral type M8.5 to M9. It shows strong Hα emission and weak Na I absorption, both indicative of a young age. The faint object is clearly detected and resolved in our optical and infrared images, with a FWHM of 0.18'' in the FORS2 image. The faint object's proper motion, based on two year epoch difference, is consistent with the proper motion of CoD-33 ° 7795 by 5 Gaussian σ significance. From three different theoretical pre-main sequence models, we estimate the companion mass to be between ∼15 and 40Mjup, assuming the distance and age of the primary. A slight offset between the VLT and HST images with an epoch difference of two years can be interpreted as orbital motion. The probability for chance alignment of such a late-type object that close to CoD-33 ° 7795 with the correct proper motion is below 7x10–9. Hence, the faint object is physically associated with CoD-33 ° 7795, the 4th brown dwarf companion around a normal star confirmed by both spectrum and proper motion, the first around a pre-main sequence star.

Abstract Copyright:

Journal keyword(s): stars: binaries: visual - stars: individual: CoD-33 7795 - stars: late-type - stars: pre-main sequence

Simbad objects: 17

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Number of rows : 17

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 LP 412-31 LM* 03 20 59.7107396327 +18 54 22.772041176   20.5 18.881 16.904 14.484 M8V 110 0
2 [RRN96] GG Tau Bb TT* 04 32 30.28224 +17 31 30.3024           M6+M7.5 76 1
3 HD 42581B BD* 06 10 34.80 -21 52 00.0           T6.5 463 0
4 LP 666-9 LM* 08 53 36.1607609203 -03 29 32.201339067     18.959 16.781 14.487 M9Ve 225 0
5 G 196-3B BD* 10 04 20.6389184345 +50 22 59.448807780           L3beta 91 0
6 LP 315-53 LM* 10 16 34.6688372711 +27 51 48.825074312   19.5 18.946 16.858 14.555 M8V 58 0
7 NAME TW Hya Association As* 11 01.9 -34 42           ~ 826 0
8 LP 732-20 PM* 11 20 26.2970231070 -14 40 02.326804415           M5Ve 38 0
9 CD-33 7795B LM* 11 31 55.2500 -34 36 25.200     20.40   15.8 M8.5/9e 118 0
10 CD-33 7795 TT* 11 31 55.2603055856 -34 36 27.214242128   12.97 11.524 11.150 9.150 M2Ve 176 0
11 BR B1222-1221 LM* 12 24 52.1859545516 -12 38 35.708340589           M8e 46 0
12 LP 271-25 LM* 14 28 43.2272685950 +33 10 39.245755294   21.2   17.8   M9Ve 233 0
13 GJ 570 D BD* 14 57 14.96256 -21 21 47.7504           T8 195 1
14 TVLM 868-110639 LM* 15 10 16.8383355861 -02 41 08.050707379     20.505 18.035 15.664 M9V 55 0
15 VB 10 Er* 19 16 57.6103282334 +05 09 01.588675251     17.30     M8V 436 1
16 * eta Tel PM* 19 22 51.2064652963 -54 25 26.152538950   5.035 5.020   4.99 A0V+M7/8V 189 0
17 CPD-54 9339B * ~ ~           ~ 1 1

    Equat.    Gal    SGal    Ecl

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2020.10.21-15:09:04

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