A Search for Very Low-mass Stars and Brown Dwarfs in the Young sigma Orionis Cluster

Astronomy and Astrophysics – Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

Accepted for publication in ApJ Main Journal. 32 pages of text and tables + 9 pages of figures. Figures 3a and 3b (gif format)

Scientific paper

10.1086/307583

We present a CCD-based photometric survey covering 870 sq. arcmin in a young stellar cluster around the young multiple star sigma Orionis. Our survey limiting R, I, and Z magnitudes are 23.2, 21.8, and 21.0, respectively. From our colour-magnitude diagrams, we have selected 49 faint objects, which smoothly extrapolate the photometric sequence defined by more massive known members. Adopting the currently accepted age interval of 2-10 Myr for the Orion 1b association and considering recent evolutionary models, our objects may span a mass range from 0.1 down to 0.02 Msun, well within the substellar regime. Follow-up low-resolution optical spectroscopy (635-920 nm) for eight of our candidates (I=16-19.5) shows that they have spectral types M6-M8.5 which are consistent with the expectations for true members. Compared with their Pleiades counterparts of similar types, Halpha emission is generally stronger, while NaI and KI absorption lines appear weaker, as expected for lower surface gravities and younger ages. Additionally, TiO bands and in particular VO bands appear clearly enhanced in our candidate with the latest spectral type, SOri 45 (M8.5, I=19.5), compared to objects of similar types in older clusters and the field. We have estimated the mass of this candidate at only 0.020-0.040 Msun, hence it is one of the least massive brown dwarfs yet discovered. We also discuss in this paper the potential role of deuterium as a tracer of both substellar nature and age in very young clusters.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

A Search for Very Low-mass Stars and Brown Dwarfs in the Young sigma Orionis Cluster 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 A Search for Very Low-mass Stars and Brown Dwarfs in the Young sigma Orionis Cluster, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Search for Very Low-mass Stars and Brown Dwarfs in the Young sigma Orionis Cluster will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-164482

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.