Spectroscopy of nova 2008-10b in M31 in rebrightening

ATel #1871; E. Barsukova, S. Fabrika (Special Astrophysical Observatory, Russia), K. Hornoch (Ondrejov Observatory, Czech Republic), O. Sholukhova, A. Valeev (Special Astrophysical Observatory, Russia)
on 8 Dec 2008; 22:13 UT
Credential Certification: Barsukova E.A. (bars@sao.ru)

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We obtained low resolution spectrum of the optical nova M31N 2008-10b (the first spectrum description is in ATel #1818, the first detection see in Atel #1790) on 2008 December 6.792 UT.

The nova shown rebrightenings, the brightness evolution in R-band (unless noted otherwise) from images taken by K. Hornoch, P. Kusnirak, and M. Wolf with the 0.65-m telescope at Ondrejov observatory, Czech Republic: Sept. 6.907 UT, [20.1; Oct. 8.979, 19.8; 14.919, 19.3; 23.718, 18.1; 26.046, 19.0; Nov. 1.948, 19.3; 4.071, 19.2; 5.728, 18.8; 6.729, 18.5; 8.783, 19.0; 24.692, 19.9 (V-band); 27.931, 18.9 (V-band); 28.699, 18.3; 29.801, 18.0; 30.767, 18.3; Dec. 8.785, 18.1; 8.816, 18.3 (V-band). The nova magnitude prior to the spectroscopy (December 6.775 UT) was V=18.4 +/-0.1.

The spectra were taken with the Russian 6-m telescope BTA equipped with the SCORPIO spectral camera. The spectral range was 390-755 nm, resolution 1.3 nm. We confirm the FeII-type of the nova. Our spectrum shows blue continuum with very strong hydrogen, FeII, MgII 448.1 nm, CaII H,K and NaI D_1,2 emission lines with P Cyg profiles. Equivalent widths of H_alpha and H_beta emissions are 18.9 and 4.6 nm, their widths (with taking into account the spectral resolution) FWHM = 930 and 1400 km/s correspondingly, their emission components heliocentric radial velocity is the same -330 km/s. The P Cyg profiles measured in H_alpha, H_beta and three strongest FeII lines (492.39, 501.84 and 516.90 nm) show the same velocities: a steep transition between emission and absorption -1140 km/s, an absorption peak -1550 km/s and the blue edge of absorption -2070 km/s.

Spectrum of M31N 2008-07a: