SN 2022prv: photometry and spectroscopy before brightness maximum
ATel #15547; E. A. Barsukova, A. S. Vinokurov, A. F. Valeev (Special Astrophysical Observatory, RAS), and V. P. Goranskij (SAI, Moscow University; SAO RAS)
on 11 Aug 2022; 17:01 UT
Credential Certification: Barsukova E.A. (bars@sao.ru)
Subjects: Optical, Supernovae
Optical transient
AT2022prv (PS22gjh) in the galaxy IC 1132 was observed at Lick
Observatory on 2022 July 28 and classified as SN II or LBV outburst
having absolute magnitude of -15.2 (ATEL #15530). We performed
additional observations of this transient on August 1 and 3 using
Russian 6-m telescope and SCORPIO multi-mode focal reducer (Afanasiev
V.L. & Moiseev A.V., 2005, Astron. Letters, V.31, p.194). The
comparison star for BV(RI)c photometry was the SDSS standard in the
field of IC 1132 with the position ra=235.0172, dec=20.6939. Its SDSS
magnitudes were transformed into the Vega BV(RI)c magnitudes: B=16.37,
V=15.54, Rc=15.08, Ic=14.67. UT date of observations, V magnitudes,
B-V, V-R and R-I color indices of AT2022prv were as follows:
UT
| V
| B-V
| V-R
| R-I
2022
Aug 1.88 | 17.06 | -0.03 | +0.11 | +0.01
2022
Aug 3.86 | 16.77 | -0.17 | +0.15 | -0.03
Our
observations show continuous increase of the star brightness to the
level 2 magnitudes above the Lick data. Probably the explosion did
not reach its maximum on Aug 3. On this date, the transient reached
absolute V magnitude Mv= -17.58 ± 0.15 mag. Its classification as SN
II is now undeniable.
We
have taken the blue spectrum of AT2022prv on 2022 Aug 1.90 UT
(spectral range 3760-5355 Å, spectral resolution of 5.7 Å), another
blue spectrum on 2022 Aug 3.89 UT (3670-5360 Å, 5.7 Å) and the red
spectrum on Aug 3.88 UT (5629-7338 Å, 5.0 Å). Spectra show hot blue
continuum with broad emission features. The strongest double-peak
feature is He II 4686 Å line merged with Bowen C III + N III blend.
Its equivalent width EW = -40 Å, and FWZI is of about 11000 km/s.
All the lines consist of a narrow central peak and very wide
intensive wings. FWHM of central peak of hydrogen lines was about 400
km/s on Aug 1 but expanded to 900 km/s on Aug 3. While FWZI of
hydrogen lines are between 8500 and 10200 km/s. This supernova is very
similar to the supernova 1998S in NGC 3877 (Q.-Z. Liu, J.-Y. Hu,
H.-R. Hang et al., 2000, Astron. Astrophys. Suppl. Ser. 144, p.219),
because it also has Wolf-Rayet star features in the pre-maximum
spectrum, and it has narrow emission components superposed on a broad
component same as the rare IIn type class of supernovae. The
structure of the emission lines suggests the explosion of the SN in
hydrogen-rich environment.
Spectra and map of SN 2022prv
