V392 Per ends the nova outburst much brighter than preceding quiescence
ATel #13381; U. Munari (INAF Padova), S. Moretti and A. Maitan (ANS Collaboration)
on 1 Jan 2020; 16:38 UT
Credential Certification: U. Munari (ulisse.munari@oapd.inaf.it)
Subjects: Optical, Cataclysmic Variable, Nova
Prior to its 2018 April 29 nova outburst (discovered by Y. Nakamura and
designated TCP J04432130+4721280), V392 Per was a poorly studied cataclysmic
variable rising little interest for its rare outbursts (only a few
recorded) and faintness (mag 17.5 on blue photographic plates during
quiescence).
V392 Per attracted a wide interest during its recent nova outburst (ATel #11588, , #11590 , #11594 , #11601 , #11605 ,
#11617 , #11647 , #11846, #11872 , #11905 , #11926 , #12951). Within one
day of outburst announcement, it was detected as a strong gamma-ray source
by Fermi-LAT. Both thermal and synchrotron radio emission were observed. The nova was also detected by Swift UVOT and X-ray
telescopes when the Sun-constraint finally lifted in late July.
Very wide emission lines dominated optical
spectra, with profiles composed by two broad components (FWHM~1800 km/s)
separated by 4000 km/s, with a very narrow central peak present in most lines,
especially HeII 4686. The huge strength of neon lines led to classify V392
Per as a Neon Nova, pointing to a massive progenitor for the current WD.
A large reddening E(B-V)=1.2 +/- 0.1 was inferred from interstellar lines
and DIBs, that coupled with somewhat uncertain peak V mag and Gaia DR2 distance
suggested a bright absolute magnitude, M(V)= -9.5/-10.5.
We are continuing our spectroscopic and photometric monitoring of V392
Per (cf ATel #11926) with Asiago 1.22m, 1.82m and ANS Collaboration
telescopes. PSF-fitting was carried out to deblend V392 Per from a nearby
field star to the North that we measure being stable at B=16.001, B-V=+0.972, V-R=+0.476, and
V-I=+1.052. Our most recent data for V392 Per are:
| HJD | UT date | B +/- | B-V +/- | V-R +/- | V-I +/- |
|---|
| 2458832.378 | 2019-12-14.878 | 16.048 0.020 | 0.910 0.022 | 0.697 0.039 | 1.391 0.040 |
| 2458843.350 | 2019-12-25.850 | 16.347 0.017 | 1.108 0.018 | 0.600 0.009 | 1.299 0.011 |
| 2458848.338 | 2019-12-30.838 | 15.960 0.015 | 0.947 0.016 | 0.740 0.008 | 1.382 0.012 |
| 2458849.460 | 2019-12-31.960 | 16.194 0.014 | 1.015 0.015 | 0.633 0.008 | 1.376 0.008 |
which are similar to those characterizing the whole of 2019, suggesting
that (1) the decline from outburst ended in Nov 2018, (2) there is a large
variability (tenths of a mag) from night to night, and (3) the system did
not returned to pre-outburst level, but instead stopped ~1.5 mag brighter.
The latter is nicely confirmed by visual inspection of blue and red CCD
frames, where V392 Per is similar in brightness to the nearby field star,
while on Palomar I and II plates it appears ~1.5 mag fainter.
Our most recent spectrum, for Dec 14.75 UT (3300-8000 Ang, 2.31 Ang/pix),
shows that the nova phase is over: its only remaining signature is a barely
visible trace of the double peaked [OIII] 5007, nothing else. The rest of
the spectrum closely resemble the one in quiescence presented by Liu and Hu
(2000, ApJS 128, 387): a featureless red continuum, strong interstellar
absorption features, and just weak, single peaked and narrow emission from
Halpha and HeII 4686, even weaker from HeI, and no Hbeta or higher Balmer
being visible. V392 Per was at V=17.4 at the time Liu and Hu (2000) recorded
their spectrum, on which they measured an integrated Halpha flux of
2.1x10(-15) erg/cm2sec. On our spectrum at V=15.138 the continuum is 8x
brighter, and the Ha flux is similarly 8x larger, measuring 1.6x10(-14)
erg/cm2sec. We derive a reddening corrected flux ratio
HeII/Halpha=1.8 on our spectrum.
