MASTER OT J030227.28+191754.5: WZ Sge-type dwarf nova having the largest outburst amplitude
We reported the results of our spectroscopic and photometric observations to ATel:
Within one day, the spectra had significantly changed to that of typical dwarf nova.
We also detected early superhump-like modulations. Thus this object will be the
WZ Sge-type dwarf nova having the largest outburst amplitude so far.
I have compiled the light curve of this unusual large-amplitude optical
transient using online data from ASAS-SN and ATLAS surveys available as of
09:20 UT on 2021 Nov. 29. It is posted at
Note 20+16 upper limits from two different ASAS-SN units on Nov.
25.27-25.29 UT and 25.78-25.80 UT. Not a usual observing cadence by this
instrument. Looks like ASAS-SN was also covering the IceCube neutrino
event, and just missed the optical transient by a magnitude or so!
MASTER: ATel #15067 (Zhirkov, Kechin, Lipunov et al.)
ASAS-SN: Kochanek et al., 2017
ATLAS: Tonry et al., 2018
R. Fidrich: vsnet-alert 26468
Note: MASTER-OAFA observation time was given in ATel #15067 as "5 hours
later" (after MASTER-Tavrida detection, that is). I have used MJD=59545.034
for the MASTER-OAFA point with 13.4m. Time error box (+/-30 min, or 0.02 d)
is smaller than the symbol size on the plot.
Another note: 20.8 mag. star 2" to the west-north-west of the transient is
not related to the variable itself. It has a proper motion detectable
between SDSS and Pan-STARRS epochs, and at the DSS plates is was located to
the south of the OT position. Most likely it is a red dwarf closer to the
Sun than the MASTER OT.
Finally, the progenitor has quite a blue color in SDSS:
u=22.17 g=21.95 r=21.93 i=22.19 z=22.41
Spectroscopic and Photometric follow-up of MASTER OT J030227.28+191754.5
We performed spectroscopic and photometric observations.
We propose that this object is a possible narrow-lined He nova or
very large-amplitude WZ Sge-type dwarf nova.
This object is showing enigmatic behavior. Further observations are strongly encouraged!