Optical spectra of the M31 Optical Transient
ATel #618; P. Reig (U. of Crete), D. Hatzidimitriou (U. of Crete), A. Manousakis (U. of Crete), W. Pietsch (MPE), G. Papamastorakis (U. of Crete)
on 4 Oct 2005; 14:05 UT
Credential Certification: Pablo Reig (pablo.reig@uv.es)
Subjects: Optical, Cataclysmic Variable, Nova, Transient
We carried out spectroscopic observations of the optical transient near
M31 reported in ATel #611 (RA = 00h38m54.63s DEC =+40o27'34.2" (J2000))
from the 1.3m telescope of the Skinakas Observatory in Crete (Greece) on
the nights 28 and 29 September 2005. The spectra covered the range
3800-7000 angstroms.
All the lines of the Balmer series up to H-8 appeared strongly in emission.
The equivalent widths of the H-alpha and H-beta lines (the strongest
emission features) on 28 September 2005 were -550+-25 angstrom and
-220+-20 angstrom, respectively and the FWHM 1800+-30 km/s in both lines.
In addition, Fe II triplets at 4924 (42), 5363 (48) and 6456 (74) angstrom
were seen in emission. From the acquisition images the brightness of the
source (roughly similar to the R band) is estimated to be 17.5+-0.2 mag.
The object is, therefore, very likely a classical nova that belongs to the
Fe II class, caught in the early decline phase.
