Astronomy and Astrophysics – Astrophysics
Scientific paper
1996-04-15
Astrophys.J.469:706-714,1996
Astronomy and Astrophysics
Astrophysics
25 pages, figures NOT included. Uuencoded and gzipped file. Full postscript (text and figures) available at http://www.iac.es/
Scientific paper
10.1086/177817
We present optical and near-IR spectroscopy (600--1000 nm) of 8 faint (I$>$18) very red (R--I$>$2.2) objects discovered in a deep CCD survey of the Pleiades (Zapatero-Osorio et al. 1996). We compare them with reliable cluster members like PPl 15 and Teide 1, and with several field very late-type dwarfs (M4--M9.5), which were observed with similar instrumental configurations. Using pseudocontinuum ratios we classify the new substellar candidates in a spectal sequence defined with reference to field stars of known spectral types. We also reclassify PPl 15 and Teide 1 in a self-consistent way. The likelihood of membership for the new candidates is assesed via the study of their photospheric features, Ha emission, radial velocity, and consistency of their spectral types and I magnitudes with known cluster members. Four of the new substellar candidates are as late or later than PPl~15 (M6.5), but only one, Calar 3 (M8), clearly meets all our membership criteria. It is indeed an object very similar to the brown dwarf Teide 1. Calar 3, together with Teide 1, allows one to compare the spectroscopic characteristics of Pleiades brown dwarfs with those of old very cool dwarfs. The overall spectral properties are similar, but there are slight differences in the NaI doublet (818.3 nm, 819.5 nm), VO molecular band (740 nm), and some spectral ratios, which are probably related to lower surface gravity in the young Pleiades brown dwarfs than in field stars. Finally, we propose a way of improving future CCD-based brown dwarf surveys by using narrow-band near-IR pseudocontinuum filters.
Martin Eduardo L.
Rebolo Rafael
Zapatero Osorio Maria R.
No associations
LandOfFree
Spectroscopy of New Substellar Candidates in the Pleiades: Towards a Spectral Sequence for Young Brown Dwarfs 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 Spectroscopy of New Substellar Candidates in the Pleiades: Towards a Spectral Sequence for Young Brown Dwarfs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Spectroscopy of New Substellar Candidates in the Pleiades: Towards a Spectral Sequence for Young Brown Dwarfs will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-215862