Free Access
Volume 435, Number 1, May III 2005
Page(s) L13 - L16
Section Letters
Published online 25 April 2005

A&A 435, L13-L16 (2005)
DOI: 10.1051/0004-6361:200500104


Evidence for a co-moving sub-stellar companion of GQ Lup

R. Neuhäuser1, E. W. Guenther2, G. Wuchterl1, M. Mugrauer1, A. Bedalov1 and P. H. Hauschildt3

1  Astrophysikalisches Institut, Universität Jena, Schillergäßchen 2-3, 07745 Jena, Germany
2  Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany
3  Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany

(Received 6 October 2004 / Accepted 27 March 2005)

We present a companion of the $\le$2 Myr young classical T Tauri star GQ Lup in the Lupus star forming region at $140 \pm 50$ 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 $0.7^{\prime \prime}$ 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 $7\sigma$, 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 $\log~g \simeq 2$ to 3 and $T_{\rm eff} \simeq 2000$ K with ~2  $R_{\rm jup}$ radius at $\sim $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.

Key words: low-mass stars -- substellar companions -- brown dwarfs -- extra-solar planets -- GQ Lup

SIMBAD Objects

© ESO 2005

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.