Evidence for a co-moving sub-stellar companion of GQ Lup (original) (raw)

NASA/ADS

;

• Guenther, E. W. ;
• Wuchterl, G. ;
• Mugrauer, M. ;
• Bedalov, A. ;
• Hauschildt, P. H.

Abstract

We present a companion of the ≤2 Myr young classical T Tauri star GQ Lup in the Lupus star forming region at 140 ± 50 pc from imaging, astrometry, and spectroscopy. With direct K-band imaging using VLT/NACO, we detected an object 6 mag fainter than GQ Lup located 0.7'' west of it. Compared to images obtained 2 to 5 years earlier with Subaru/CIAO and HST/PC, this object shares the proper motion of GQ Lup by 5 and 7σ, respectively, hence it is a co-moving companion. Its K-L' color is consistent with a spectral type early to mid L. Our NACO K-band spectrum yields spectral type M9-L4 with H2O and CO absorption, consistent with the new GAIA-Dusty template spectrum for log g ≃ 2 to 3 and Teff ≃ 2000 K with ~2 Rjup radius at ∼ 140 pc, hence few Jupiter masses. Using the theoretical models from Wuchterl & Tscharnuter (2003), Burrows et al. (1997), and Baraffe et al. (2002), the mass lies between 1 and 42 Jupiter masses.

Publication:

Astronomy and Astrophysics

Pub Date:

May 2005

DOI:

10.1051/0004-6361:200500104

arXiv:

arXiv:astro-ph/0503691

Bibcode:

2005A&A...435L..13N

Keywords:

• low-mass stars;
• substellar companions;
• brown dwarfs;
• extra-solar planets;
• GQ Lup;
• Astrophysics

E-Print:

4 pages with 4 figures A&amp