Astronomy and Astrophysics – Astrophysics
Scientific paper
1998-11-21
Astronomy and Astrophysics
Astrophysics
to appear in AJ, January 1999; 34 pages, (Latex format), including 10 embedded postscript figures and two tables
Scientific paper
10.1086/300686
We have used both the Low-Resolution Imaging Spectrograph and the HIRES echelle spectrograph on the Keck telescopes to obtain spectra of twelve candidate members of the Hyades cluster identified by Leggett and Hawkins (1988, 1989). All of the objects are chromospherically-active, late-type M-dwarfs, with H$\alpha$ equivalent widths varying from 1 to 30\AA. Based on our measured radial velocities, the level of stellar activity and other spectroscopic features, only one of the twelve stars has properties consistent with cluster membership. We consider how this result affects estimates of the luminosity and mass function of the Hyades cluster. Five of the eleven field stars have weak K I 7665/7699\AA and CaH absorption as compared with M-dwarf standards of the same spectral type, suggesting a lower surface gravity. Two of these sources, LH0416+14 and LH0419+15, exhibit significant lithium 6708 \AA absorption. Based partly on parallax measurements by the US Naval Observatory (Harris et al, 1998), we identify all five as likely to be young, pre-main sequence objects in or near the Taurus-Auriga association at distances of between 150 and 250 parsecs. A comparison with theoretical models of pre-main sequence stars indicates masses of less than 0.05 M$_\odot$.
Hawley Suzanne L.
Reid Iain Neill
No associations
LandOfFree
Brown dwarfs in the Hyades and beyond? 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 Brown dwarfs in the Hyades and beyond?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Brown dwarfs in the Hyades and beyond? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-282625