Dear colleagues,
I have just finished analysing my unfiltered CCD observations of
ASASSN-22ho, obtained on 2022, June 02/03 at CBA Belgium Observatory, using
a 0.40-m f/10.0 telescope and QHY-286M CMOS camera under clear skies.
Regular superhumps with an amplitude of 0.35 mag are very clearly visible in
the resulting light curve, establishing ASASSN-22ho 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
(long) superhump period of 0.0902 +/- 0.0025d. The object was at mag CV =
16.5 on Jun 03rd.
I will send my observations to AAVSO, CBA and VSNET for further analysis.
Best regards
Tonny
---
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: ASASSN-18su
Superhumps were already detected during the 2018 superoutburst
by Berto Monard. Superhumps appeared on 2018 Aug. 25.
Due to the short visibility, the period was not determined.
ASASSN-18su (UG)
https://www.aavso.org/vsx/index.php?view=detail.top&oid=623474
ASASSN-18su was discovered on 2018 August 17.
Unfortunately that outburst could be followed for only few days.
After the seasonal gap a very long fading tail can be seen in
ATLAS forced photometry data.
T. Kato wrote (vsnet-alert 22429):
"The Gaia proper motion is comparable to that of OV Boo ...
ASASSN-18su looks likely a population II CV candidate."
The current outburst was detected by Rod Stubbings at mv= 11.3
on 2022 June 28.537 UT (vsnet-outburst 28822, vsnet-alert 26852).
It had already started on June 24 and is 1.5 magnitudes fainter
than the 2018 outburst according to ASAS-SN Sky Patrol data:
https://asas-sn.osu.edu/sky-patrol/coordinate/52d16cd1-3548-431f-a7fc-326e3…
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
Asteroid Terrestrial-impact Last Alert System (ATLAS):
- Tonry et al., 2018PASP..130f4505T
TCP J22561804+4109534 (UG:)
(submitted to VSX)
RA 22h56m18.05s +41°09'54.3" (J2000.0, Pan-STARRS1)
2022 June 26.6897 UT, mag. 14.0 (CMOS camera, unfiltered)
Discoverer: Yuji Nakamura (Kameyama, Mie, Japan)
2022 06 26.6897 UT
Discovered by Yuji Nakamura, Kameyama, Mie, Japan, on two
frames (30-s exp. limiting mag 16.0) taken by 10cm/F3.0
refractor and CMOS camera. Nothing is visible at this location
on the frames taken on 2022 June 18.7097 UT (30-s exp.
limiting mag 16.0) by same instrument. --- Isao Endoh (NAOJ)
http://www.cbat.eps.harvard.edu/unconf/followups/J22561804+4109534.html
Complete ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S
and Kochanek et al. 2017PASP..129j4502K) light curve and data:
https://asas-sn.osu.edu/sky-patrol/coordinate/a342649c-16c0-43e6-86f6-933b9…
TCPJ22561804+4109534 20220624.4688 <17.55g ASN
TCPJ22561804+4109534 20220626.3301 14.70g ASN
TCPJ22561804+4109534 20220626.3314 14.76g ASN
TCPJ22561804+4109534 20220626.3326 14.74g ASN
TCPJ22561804+4109534 20220626.3379 14.71g ASN
TCPJ22561804+4109534 20220626.3391 14.72g ASN
TCPJ22561804+4109534 20220626.3404 14.69g ASN
Time-resolved and multiband (V, B, ...) photometry are required
(spectroscopy is also encouraged).
Clear skies,
Patrick