September 2021 - vsnet-campaign-dn - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-campaign-dn 16008] ASASSN-21sb: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 27 Sep '21

27 Sep '21

Dear colleagues, I have just finished analysing my time-series observations of ASASSN-21sb, obtained on 2021, Sep 25/26 and Sep 26/27 at resp. CBA Extremadura Observatory and CBA Belgium observatory, using 0.40-m telescopes with SX-46 CCD and QHY-268M CMOS camera's. Regular superhumps with an amplitude of 0.32 mag are clearly visible in the resulting light curve, establishing ASASSN-21sb 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 0.0589 +/- 0.0003d. The object was at mag CV = 16.2 on Sep 27th. 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

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[vsnet-campaign-dn 16007] IPHASJ190812.63+045728.1: eclipsing dwarf nova in the period gap
by Taichi Kato 27 Sep '21

27 Sep '21

IPHASJ190812.63+045728.1: eclipsing dwarf nova in the period gap From ZTF data. Porb=0.1056882(3) d. Eclipse epoch: BJD 2458662.020. The behavior up to now suggests an SS Cyg star, but a search for a superoutburst would be interesting.

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[vsnet-campaign-dn 16006] CRTS J145921.8+354806 superoutburst
by Taichi Kato 23 Sep '21

23 Sep '21

CRTS J145921.8+354806 superoutburst YYYYMMDD(UT) mag observer 20210921.1771 15.703zr (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210923.1584 15.411zg (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210923.1746 15.803zr (Zwicky Transient Facility Lasair (Masci+ 2019))

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[vsnet-campaign-dn 16005] V544 Her faded after double outburst and apparently rebrightened
by Taichi Kato 22 Sep '21

22 Sep '21

V544 Her faded after double outburst and apparently rebrightened YYYYMMDD(UT) mag observer 20210819.5030 <156c (Yutaka Maeda) 20210820.5016 <146c (Yutaka Maeda) 20210824.1742 15.119zr (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210824.1938 14.913zg (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210826.1947 15.308zr (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210827.5030 151:c (Yutaka Maeda) 20210828.1876 15.252zg (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210828.1877 15.252zg (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210828.2713 15.354zr (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210828.2715 15.354zr (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210828.901 15.30C (Gary Poyner) 20210828.9028 15.22C (Masao Funada) 20210829.4567 157:cG (Yutaka Maeda) 20210830.8756 16.63C (Masao Funada) 20210831.2067 16.965zg (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210831.2069 16.965zg (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210831.4373 <164c (Yutaka Maeda) 20210831.5071 <166C (Masayuki Moriyama) 20210903.2085 17.666zr (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210903.2086 17.666zr (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210903.2667 17.995zg (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210905.1945 15.505zr (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210907.2273 15.298zr (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210907.2275 15.298zr (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210908.4314 155:c (Yutaka Maeda) 20210909.1497 15.498zr (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210909.4912 150cG (Yutaka Maeda) 20210911.1659 15.415zg (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210916.2071 18.551zg (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210919.1506 17.415zg (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210919.1749 17.114zr (Zwicky Transient Facility Lasair (Masci+ 2019))

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[vsnet-campaign-dn 16004] LL And: stage A superhumps and mass ratio
by Taichi Kato 22 Sep '21

22 Sep '21

LL And: stage A superhumps and mass ratio Kyoto U. team, Crimean Astrophys. Obs. team, Itoh-san, Alexandra Zubareva, Tonny Vanmunster, Tamas Tordai, Filipp Romanov and Kiyota-san have reported observations. The object started to show well-detectable superhumps since Sep. 20. The current period (stage A) is 0.0579(1) d. This period corresponds to q=0.143(5). This value is consistent with the result in https://ui.adsabs.harvard.edu/abs/2004PASJ...56S.135K/abstract This object is likely an SU UMa star (rather than a WZ Sge star) as judged from the mass ratio despite the very long supercycle. The lack of strong early superhumps appears to be consistent with this classification.

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[vsnet-campaign-dn 16003] ASASSN-19ax superhump period
by Taichi Kato 22 Sep '21

22 Sep '21

ASASSN-19ax superhump period Itoh-san, Kiyota-san, Tonny Vanmunster and Tamas Tordai have reported observations. The superhump period is established to be 0.10012(2) d. There is currently no period variation.

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[vsnet-campaign-dn 16002] LL And showing regular superhumps
by tonny.vanmunster＠gmail.com 21 Sep '21

21 Sep '21

Dear colleagues, I obtained another LL And time series last night (2021, Sep 20/21) at CBA Extremadura Observatory in Spain, using a 0.40-m f/5.1 telescope and SX-46 CCD camera under clear skies. Looking at the resulting light curve, it seems that early superhumps have now been replaced by regular superhumps with an amplitude of 0.15 mag. The object was at mag CV = 13.9 on Sep 21st. 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

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[vsnet-campaign-dn 16001] TCP J20115874-1922459: likely a dwarf nova outburst (mag. 15, in Capricornus)
by Patrick Schmeer 21 Sep '21

21 Sep '21

TCP J20115874-1922459 = BraTS-SON-T2-032 (UG:) https://www.aavso.org/vsx/index.php?view=detail.top&oid=2224741 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/eaad0624-e1cc-4b94-81ea-82a5d… Outburst amplitude 7 magnitudes. Already in outburst (orange mag. ~15.4) on 2021 September 20.358 UT according to ATLAS data. Time-resolved photometry is encouraged. Clear skies, Patrick ------- 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

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[vsnet-campaign-dn 16000] ASASSN-19ax: new long period SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 18 Sep '21

18 Sep '21

Dear colleagues, I have just finished analysing my unfiltered observations of ASASSN-19ax, obtained on 2021, September 17/18 at CBA Belgium Observatory (0.40-m f/10.0 telescope, QHY-268M CMOS, clear then clouds) and at CBA Extremadura Observatory (0.40-m f/5.1 telescope, SX-46 CCD, clear then clouds). The combined lightcurve covers a time span of 7.2h and clearly shows the presence of superhumps with an amplitude of 0.26 mag, establishing ASASSN-19ax 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 0.1015 +/- 0.0024d, well above the period gap (as suspected by Taichi Kato in vsnet-alert 26256). The object was at mag CV = 13.5 on Sep 18th. 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

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[vsnet-campaign-dn 15999] ASASSN-15sn possible superoutburst
by Taichi Kato 18 Sep '21

18 Sep '21

ASASSN-15sn possible superoutburst Known SU UMa star. YYYYMMDD(UT) mag observer 20210908.6476 <153c (Yutaka Maeda) 20210916.2647 15.384zr (Zwicky Transient Facility Lasair (Masci+ 2019))

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