Spectrum and proper motion of a brown dwarf companion of the T Tauri star CoD-33 7795
| dc.creator | Neuhaeuser, R. | |
| dc.creator | Guenther, E. W. | |
| dc.creator | Petr, M. G. | |
| dc.creator | Brandner, W. | |
| dc.creator | Huelamo, N. | |
| dc.creator | Alves, J. | |
| dc.date | 2000-07-20 | |
| dc.date.accessioned | 2026-07-07T01:54:28Z | |
| dc.date.available | 2026-07-07T01:54:28Z | |
| dc.description | We present optical and infrared spectra as well as the proper motion of an H=12 mag object 2" off the ~5 mag brighter spectroscopic binary star CoD-33 7795 (=TWA-5), a member of the TW Hya association of T Tauri stars at ~55 pc. It was suggested as companion candidate by Lowrance et al. (1999) and Webb et al. (1999), 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 H-alpha 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 sigma significance. From three different theoretical pre-main sequence models, we estimate the companion mass to be between ~15 and 40 M_jup, 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 7e-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. | |
| dc.description | A&A letters in press | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0007301 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0007301 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/1362 | |
| dc.subject | Astrophysics | |
| dc.title | Spectrum and proper motion of a brown dwarf companion of the T Tauri star CoD-33 7795 | |
| dc.type | text |