Spectroscopic identification of the high-amplitude variable star in Leo
ATel #951; A. Rau, E. O. Ofek (both Caltech Optical Observatories), M. Lacy & G. Wilson (both IPAC, Caltech)
on 23 Nov 2006; 01:53 UT
Credential Certification: Eran Ofek (eran@wise.tau.ac.il)
Subjects: Optical, Transient, Variables
We report on follow-up spectroscopy of the high-amplitude variable
star in Leo (see Christensen et al., CBET#746) with the COSMIC
spectrograph mounted on the Hale-5m telescope at Palomar
Observatory. Observations were performed on UT 2006 November 21.55
and covered a wavelength range from 4000 to 8200 Angstrom with a
resolution of ~8 Angstrom.
The spectrum shows a very blue continuum and prominent Balmer
absorption lines (H_epsilon to H_alpha) together with a weak HeI
P-Cygni profile around 5876 Angstrom. The best fitting stellar
template is a B3-4V star.
We note that the observered high amplitude (7 magnitudes in the
g-band) is not expected for B-stars. Furthermore, the photometric
colors of the quiescent SDSS counterpart (u-g=0.09, g-r=0.11,
r-i=-0.21, i-z=0.39) are incompatible with the colors of main sequence
stars or giants of any type.
We further inspected images taken using the Near-Earth Asteroid
Tracking (NEAT) project during 1998 (Jan, Feb), 2002 (Feb, Mar, Apr,
May) and 2005 (May). No previous outburst of this source is detected.
