MGAB-V359: more likely very unusual IP below the period minimum
I have analyzed thr ZTF data and confirmed the two periods
found by G. Murawski.
The amplitudes, however, are too large for an AM CVn star.
The 0.0351788-d period has an amplitude of 1.5 mag.
The 0.0239743-d period has an amplitude of 1.1 mag.
The beat period of 0.0756893 d has to maxima per cycle.
It is also unusual for an AM CVn star to have a secondary
period much shorter than the orbital one.
The profile of the light curve is boxy rather than sinusoidal
(suggesting emission from magnetic poles).
This object looks more likely an IP below the period minimum,
but with polar-like large variations like Romanov V48 we suggested.
MGAB-V359 also has a bright ROSAT counterpart:
122016.2 +565454 (2000.0) 2RXP_J122016.3+565455 0.2251P -0.81 -0.41 931030
122016.4 +565451 (2000.0) 1RXPJ122016+5654.8 0.2160 -0.81 -0.43
V482 Cygni (RCB)
The current fading began in early May 2022 according to
ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S
and Kochanek et al. 2017PASP..129j4502K) data (complete):
Photometric (e.g. V band) and spectroscopic observations
are encouraged. The Vmag range in VSX is 10.65 - <14.5.
Gary Poyner wrote on Monday, 23 May 2022 at 15:35:18 UTC:
There is a suggestion that the RCB star V482 Cyg may be fading.
The star has been pretty much inactive since June 1996 when it
faded to magnitude 13.0 and recovered to maximum brightness
12 months later (a deeper fade to magnitude 15.0 occured in 1990).
Since then there have been small amplitude variations of 0.5 mag
either side of magnitude 11.0. Latest magnitude in the AAVSO
database is 11.9mv.
Charts are available from both BAAVSS and AAVSO.
Further observations are requested.
Gary Poyner FRAS