The AM CVn-type object NSV 1440 is in bright outburst.
NSV 1440 210830.519 129
Tetoora Road Observatory
Telescope: "Infinity" 22" f/3.8
ASASSN-V J205543.90+240033.5: combination of three periods
Josch Hambsch and Tonny Vanmunster have reported
"ASASSN-V J205543.90+240033.5: another white dwarf pulsar?"
Their observations indicate that the global
variation is a combination of the longer period 10.803 d
and a shorter period 0.203424(1) d (determined from
the ZTF data). These variations create the dispersion
in figure 2 of the above paper.
Their data also confirmed the short period of
0.0067876(7) d (amplitude 0.07 mag).
This must be a very interesting CV-like object
and further observations (including spectroscopy)
PNV J05393469+5715159 = ZTF21abuzuih: Possible WZ Sge-type object
Large outburst amplitude of 8 mag. The fading rate is 0.15 mag/d. Possible WZ Sge-type object.
PNV J05393469+5715159 2021 08 27.8730* 05 39 34.69 +57 15 15.9 13.57C Cam R -
2021 08 27.8730
Guoyou Sun (Xingming Observatory), Quanzhi Ye (Department of Astronomy, University of Maryland), Xing Gao (Xingming Observatory), report the discovery of a possible nova (13.57 C) which is 21.923 gmag in Pan-STARRS DR1 catalogue (PS1 objID 176700848943505888). The transient was discovered on several 60-s survey images (limiting mag about 19.0) taken Xing Gao by at Xingming Observatory-KATS, Nanshan (N86) around Aug. 27.87299, 2021 UT using a unfiltered CCD (0.28-m f/2.2 reflector). Images can be found at: http://xjltp.china-vo.org/XMK001.html
053934.647 +571515.678 PS1_176700848943505888 g=21.9230(0.1727) r=21.6724(0.0988) i=-(-) z=-(-) y=-(-)
20210819.590 <17.788g ASN
20210822.589 19.422o ATF
20210824.444 13.912zg ZLR
20210825.585 13.973g ASN
20210827.447 14.363zg ZLR
20210827.487 14.386zr ZLR
20210827.581 14.436g ASN
20210827.873 13.57C (Xingming Observatory-KATS)
RA and DEC: 03 39 33.881 +22 31 40.33 (Gaia EDR3, equinox J2000.0, epoch J2016.0)
Magnitude: V= 10.5 (outside eclipse)
The next eclipse of this newly discovered variable star is predicted for 2021 Aug 28.80 UT.
Time-resolved photometry and spectroscopy are encouraged.
The following text was written by Ulrich Bastian on 11 August 2021:
Back in January 2021, the bright star TYC 1799-1159-1 (9th-magnitude in the red wavelength range;
in the visual range it is about 10th magnitude) was serendipitously discovered by German amateur
Martin Gertz to be an eclipsing binary. In the night to March 7, a second minimum was observed,
and an earlier third dimming by 0.5 mag was found in the ASAS-SN database. All three are
separated by multiples of 34.987 days, so the fact is confirmed. However, the character of the light
curve (period, 0.5 mag depth of the eclipse, shape and width of the minima), together with the
parallax and HRD location of the star from Gaia eDR3, seemingly makes it an astrophysical impossibility.
No conceivable combination of two stars could produce this whole set of characteristics, while at the
same time the triple occurrence of the minima completely excludes any interstellar or solar-system
Thus, more observations during the forthcoming observing season 2021/2022 are urgently desired.
The star is located at 3 39 33.8 +22 31 41 (J2000), about 2 degrees south-west of the Pleiades' centre
(it is not a cluster member). Minima are predicted to occur at the following times:
Ep. no. JD-2459000 Date MEZ/MESZ UTC comment
- 4 (140.365) (ASAS-SN dimming)
- 3 175.401 21.11.2020 22:37 MEZ 21:37 observed Gertz
+ 0 280.362 06.03.2021 21:42 MEZ 20.42 observed Gertz
+ 5 455.297 28.08.2021 21:08 MESZ 19:08 Europe no; Japan?
+ 6 490.284 02.10.2021 20:49 MESZ 18:49 Europe no; Japan?
+ 7 525.271 06.11.2021 19:30 MEZ 18:30 Europe yes
+ 8 560.258 11.12.2021 19:11 MEZ 18:11 Europe & US yes,
+ 9 595.245 15.01.2022 18:53 MEZ 17:53 Europe & US yes
+10 630.232 19.02.2022 18:34 MEZ 17:34 Europe & US yes
The formal uncertainties of the times are less than 0.5 hours at the beginning and less than 1 hour
towards the end of the observing season, but given the completely unclear nature of the system,
period changes cannot be excluded. Also, the duration of the minima is unpredictable: The first
lasted 40 minutes in total, the second took more than 1 hour for just the recovery from minimum
to normal light. It is therefore desirable to get as much data coverage as possible for intervals of
plus/minus one day around the predicted minima. Given the clear inconsistency of the two recorded
minima shapes - and given the fact hat no dimmings have been found in several photometric
archives before Oct 2020 - it is even possible that no further minima will occur at all.