High-resolution optical spectroscopy of Nova V392 Per

ATel #11605; T. Tomov (Nicolaus Copernicus University, Torun, Poland), I. Stateva, S. Georgiev, R. Konstantinova-Antova, K. Stoyanov (Institute of Astronomy and NAO, Bulgaria)
on 4 May 2018; 10:50 UT
Credential Certification: Kiril Stoyanov (kstoyanov@astro.bas.bg)

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We obtained two spectra of the Nova V392 Per (ATel #11588; ATel #11601) with the ESPERO echelle spectrograph (Bonev et al. 2017, BlgAJ 26, 67) at Rozhen observatory (Bulgaria), on 2018 May 1 18.74 UT and May 2 18.80 UT. The spectra cover the range of 4400-9000 Å with a resolving power of ~30 000. The spectrum of the Nova is dominated by very broad emission lines with a complex shape. The strongest lines in our spectra are Hα, Hβ, FeII 42 multiplet, CaII IR triplet, OI 7774Å and 8446Å. HeI lines 5876Å and 6677Å are relatively weak with an obvious increase of the emission intensity during the second night. The FWHM measured for the Hα and Hβ emission lines is 5600±200 km/s. In their profiles, three peaks with radial velocities of about -2000 km/s, -250 km/s and 1900 km/s are apparent. Weak P Cyg absorption components are also visible in the Hα and Hβ profiles. We measured the radial velocity to be about -4000 km/s for one absorption component in Hα and about -3700 km/s and -4100 km/s for two absorptions in Hβ. Three very weak absorptions of HeI 5876Å with radial velocities of about -1350 km/s, -3035 km/s and -3350 km/s are also visible in the spectrum.

The DIBs 5780Å, 5797Å, 6614Å and the interstellar lines NaI and KI are very strong. The interstellar lines show two components with radial velocities -23.7±1.5 km/s and 3.5±0.3 km/s respectively. Using the relations of Munari & Zwitter (1997, A&A 318, 269) for KI (the NaI lines are saturated and not usable) and of Puspitarini et al. (2013, A&A 555, 25) for the DIBs, we derived an interstellar excess E(B-V)~1.18+/-0.10 mag. From Gaia DR2 (Gaia Collaboration et al. 2016, A&A 595, 1; Gaia Collaboration et al. 2018b, A&A, special issue for Gaia DR2) we can determine the distance to V392 Per as 3.9±0.8 kpc. Adopting V=6.34 mag from the AAVSO light curve as maximum brightness, for the absolute magnitude at maximum we obtain Mv=-10.3±0.3 mag.