The optical flickering from MWC 560 is still missing
ATel #14988; R. Zamanov, K. Stoyanov, V. Marchev (Institute of Astronomy and NAO, Bulgarian Academy of Sciences), D. Marchev, T. Atanasova, N. Pavlova (Shumen University)
on 20 Oct 2021; 12:19 UT
Credential Certification: Kiril Stoyanov (kstoyanov@astro.bas.bg)
Subjects: Optical, Binary, Cataclysmic Variable, Variables
We performed photometric observations of the jet-ejecting symbiotic star MWC 560 in Sloan g' and r' bands with the 40 cm telescope of the Shumen University "Episkop K. Preslavski" Bulgaria (Kjurkchieva et al. 2020, BlgAJ, 32, 113).
The observations show an absence of optical flickering with amplitude greater than 0.05 mag.
The Table below lists the date of each observation, the band, the UT-start and UT-end of the run, the number of data points, the average brightness during the run (in magnitudes), the standard deviation of the brightness during the run, the upper limit of the peak-to-peak amplitude.
| DATE - BAND |
UTstart - UTend |
Npts
|
average / sigma
|
upper limit
|
|
hh:mm hh:mm |
|
[mag] / [mag] |
[mag]
|
| 22 February 2021 g' |
19:16 - 21:45 |
363 |
8.91 / 0.014
|
< 0.07 |
| 22 February 2021 r' |
19:16 - 21:45 |
361 |
8.51 / 0.015
|
< 0.08 |
| 20 October 2021 g' |
0:30 - 2:28 |
216 |
8.55 / 0.011
|
< 0.05 |
| 20 October 2021 r' |
0:30 - 2:28 |
214 |
8.24 / 0.013
|
< 0.06
|
The flickering of MWC 560 was visible in all observations obtained between 1984 and May 2018 (e. g. Lucy et al. 2020, MNRAS,492, 3107).
It disappeared in October 2018 (ATel #
12227) and not detected since then.
Most probably, the accretion disc is in an unusual state - very bright and stable.
Optical flickering from MWC 560 is still missing.
