Optical evolution of Nova Ophiuchi 2007 = V2615 Oph

Abstract

The moderately fast Nova Oph 2007 reached maximum brightness on March 28, 2007 at V=8.52, B-V=+1.12, V-Rc=+0.76, V-Ic=+1.59 and Rc-Ic=+0.83, after fast initial rise and a pre-maximum halt lasting a week. Decline times were t(V,2)=26.5, t(B,2)=30, t(V,3)=48.5 and t(B,3)=56.5 days. The distance to the nova is d=3.7 kpc, the height above the galactic plane z=215 pc, the reddening E(B-V)=0.90 and the absolute magnitude at maximum M(V,max)=-7.2 and M(B,max)=-7.0. The spectrum four days before maximum resembled a F6 super-giant, in agreement with broad-band colors. It later developed into that of a standard 'FeII'-class nova. Nine days past maximum, the expansion velocity estimated from the width of H$\alpha$ emission component was 730 km/s, and the displacement from it of the principal and diffuse enhanced absorption systems were 650 and 1380 km/s, respectively. Dust probably formed and disappeared during the period from 82 to 100 days past maximum, causing (at peak dust concentration) an extinction of Delta B=1.8 mag and an extra Delta E(B-V)=0.44 reddening.Comment: accepted in press by MNRA

An extensive optical study of V2491 Cyg (Nova Cyg 2008 N.2), from maximum brightness to return to quiescence

“…These behaviors are normal for novae, for ex. similar to those displayed by the moderately slow FeII nova V2615 Oph (N Oph 2007, Munari et al, 2008a.…”

“…The network has been used already for detailed studies of some other recent novae (e.g. Munari et al, 2008aMunari et al, ,b, 2010b.…”

Photometric and spectroscopic variability of the FUor star V582 Aurigae

“…The first low-dispersion spectrum obtained on 2009 August 6 is dominated by absorption lines of the Balmer series (Hα and Hβ), Na I D, and Ba II 6497 Å, and emission lines are not noticed. The spectrum appears like a supergiant of temperature about 5500 K, but the Li I 6707 Å line is weak, not emerging above the noise (Munari et al 2009). On the highresolution spectrum obtained on 2010 January 15, the Hα line and Na I doublet show the P Cyg profiles, which are typical of FUor stars (Fig.…”

“…Samus (2009) examined the brightness of the star on photographic plates from the Moscow collection (1965−1992) and on the images from the Digitized Sky Survey (1954−1993), which suggests that the increase in brightness started between 1982 and 1986. Munari et al (2009) obtained the first low-resolution spectrum of V582 Aur on 2009 August 6 and registered the presence of absorption lines of the Balmer series, Na I D and Ba II (λ 6496) and the absence of the Li I (λ 6707) line in the spectrum. The photometric observations of V582 Aur reported by Munari et al (2009) show the star near to maximal brightness on 2009 August 5 and 6.…”

“…Munari et al (2009) obtained the first low-resolution spectrum of V582 Aur on 2009 August 6 and registered the presence of absorption lines of the Balmer series, Na I D and Ba II (λ 6496) and the absence of the Li I (λ 6707) line in the spectrum. The photometric observations of V582 Aur reported by Munari et al (2009) show the star near to maximal brightness on 2009 August 5 and 6. Using the midinfrared part of the AKARI All-Sky Survey, Takita et al (2010) identified V582 Aur as a T Tauri star candidate.…”