X-shooter observations of the accreting brown dwarf J053825.4-024241

Details X-shooter observations of the accreting brown dwarf J053825.4-024241 X-shooter observations of the accreting brown dwarf J053825.4-024241

2010-12-13

arxiv.org/abs/1012.2649v1

Astronomy and Astrophysics

Astrophysics

Solar and Stellar Astrophysics

4 pages, 4 figures

Scientific paper

We present the first observations of a probable brown dwarf, obtained with the new spectrograph X-shooter mounted on the UT2@VLT. The target (2MASS J053825.4-024241) is a 0.06 Msun object in the star-formation region sigma Orionis. The X-shooter spectrum covers simultaneously the whole range from UV to NIR (300-2500 nm). The J053825.4-024241 spectrum is rich in emission lines that are typical of accreting young object and clearly shows the Balmer jump. Moreover, many photospheric atomic and molecular absorption lines yield the spectral type and confirm that the object is young. We compute the mass accretion rate from all available observed accretion diagnostics. We find that there is a large spread in the Macc values (up to a factor 40) that is not caused by variability; some of this spread may be intrinsic, i.e., owing to different physical conditions of the emitting region for the same Macc. However, within the large error bars all Macc measurements agree, and the mean value is logMacc ~ -9.86 +- 0.45 Myr. The hydrogen Balmer lines are clearly detected up to n=25. Their ratios suggest that the emitting region is cold (T~2000-3000 K), dense and in thermal equilibrium (LTE), and that the lines are optically thick up to n~21. We briefly discuss the implications of this result for magnetospheric accretion models.

Affiliated with

Also associated with

No associations

Rating

X-shooter observations of the accreting brown dwarf J053825.4-024241 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with X-shooter observations of the accreting brown dwarf J053825.4-024241, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and X-shooter observations of the accreting brown dwarf J053825.4-024241 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-26698