[ Previous | Next | ADS ]

Spectroscopic Observations of the Unusual Transient TCP J00452884+4154095 in M31

ATel #4503; A. W. Shafter (SDSU), K. Hornoch (Astronomical Institute, Ondrejov, Czech Republic), J. Vrastil (Astronomical Institute, Charles U., Prague, Czech Republic) R. Ciardullo (PSU), M. J. Darnley, M. F. Bode (Liverpool JMU)
on 20 Oct 2012; 21:41 UT
Credential Certification: Allen W. Shafter (aws@nova.sdsu.edu)

Subjects: Optical, Nova, Transient

Referred to by ATel #: 5607, 5611, 5627, 6540

We report spectroscopic observations of the M31 transient TCP J00452884+4154095 (tentatively identified as M31N 2012-10a) discovered on 2012 Oct. 18.68 UT by K. Nishiyama and F. Kabashima at m = 18.9 (unfiltered). Subsequent photometry on 2012 Oct. 19.718 UT and 19.730 UT gives R = 18.45 +/- 0.04 and I = 18.42 +/- 0.06, respectively. The transient is located approximately 31'E and 38'N of the center of M31, and is coincident within measurement uncertainties with the reported positions of two recent M31 nova candidates, M31N 2008-12a and 2011-10e (ATel #3725, #3727, #3728).

At our request, a spectrum (410–900 nm) of TCP J00452884+4154095 was obtained by S. Rostopchin with the 9.2m Hobby-Eberly Telescope (+ Marcario Low-Resolution Spectrograph) on 2012 Oct. 20.34 UT, approximately 2 days post discovery. The spectrum (see link below) is dominated by strong and moderately broad Balmer (FWHM Hα ~ 2250 km/s), N II, N III, and He I emission features, superimposed on a slightly blue continuum. Our observations are consistent with the identification of TCP J00452884+4154095 as a relatively faint nova in M31, and a member of the He/N spectroscopic class. Furthermore, the spatial coincidence with M31N 2008-12a and 2011-10e suggests that the object is a recurrent nova, but given the apparently low luminosity and the unusually short interval between brightenings, it is unclear whether the current outburst represents a new eruption, or a re-brightening of the recent 2011 event. Further observations are encouraged to monitor the photometric and spectroscopic evolution of this very unusual object. We thank Koichi Nishiyama and Fujio Kabashima (Miyaki-Argenteus Obs.) for alerting us to this latest outburst. A.W.S. thanks the NSF for support through AST-1009566.

HET Spectra of Local Group Novae