Dear colleagues,
I have been collecting unfiltered CCD observations of ASASSN-21tr over the
past several nights at CBA Extremadura Observatory, using a 0.40-m f/5.1
telescope and SX-46 CCD camera under (mostly) clear skies.
The collected light curves did not show obvious periodic modulations, with
the exception of last night Oct 25/26, 2021. Regular superhumps with an
amplitude of 0.11 mag are clearly visible, establishing ASASSN-21tr as a new
SU UMa-type dwarf nova. A period analysis using the ANOVA, Lomb-Scargle,
Generalized-Lomb-Scargle and PDM methods (Peranso 3.0), yields a combined
superhump period of 0.0647 +/- 0.0012d. The object was at mag CV = 15.4 on
Oct 25th.
I will send my observations to AAVSO, CBA and VSNET for further analysis.
Best regards
Tonny
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Tonny Vanmunster
CBA Belgium Observatory
CBA Extremadura Observatory
http://www.cbabelgium.com
PERANSO : The Light Curve and Period Analysis Software
http://www.peranso.com
Re: OGLE-MC-DN-0008 in outburst! (since Oct. 19)
It looks very likely from the light curve that
this object developed superhumps in these days
following a smooth decline. Superhumps should be
present now.
OGLE-MC-DN-0008 (UG)
https://www.aavso.org/vsx/index.php?view=detail.top&oid=478014
I just had a look at the latest ASAS-SN Sky Patrol data for
OGLE-MC-DN-0008 and noticed that this dwarf nova is
undergoing a rare outburst (which started on Oct. 17 or 18):
https://asas-sn.osu.edu/sky-patrol/coordinate/d946ac58-407a-41d0-888f-842db…
Time-resolved photometry is urgently required.
Clear skies,
Patrick
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References:
All-Sky Automated Survey for Supernovae (ASAS-SN) Sky Patrol:
- Shappee et al., 2014ApJ...788...48S
- Kochanek et al., 2017PASP..129j4502K