September 2021 - vsnet-alert - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-alert 26263] 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-alert 26262] LL And showing regular superhumps
by tonny.vanmunster＠gmail.com 22 Sep '21

22 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 Looking at the resulting light curve, it seems that early superhumps have now been replaced by regular superhumps with an amplitude of 0.15 mag.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-alert 26261] TCP J20115874-1922459: likely a dwarf nova outburst (mag. 15, in Capricornus)
by Patrick Schmeer 22 Sep '21

22 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-alert 26260] 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-alert 26259] 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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[vsnet-alert 26258] Gaia17asx possible superoutburst
by Taichi Kato 18 Sep '21

18 Sep '21

Gaia17asx possible superoutburst Type from ZTF data. There was an outburst in 2021 June (normal). The next superoutburst is overdue and the current one is expected to be s super. YYYYMMDD(UT) mag observer 20210901.2764 21.222zg (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210903.3009 22.190zg (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210905.3053 21.613zg (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210909.3198 21.586zg (Zwicky Transient Facility Lasair (Masci+ 2019)) 20210916.2764 16.713zg (Zwicky Transient Facility Lasair (Masci+ 2019))

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[vsnet-alert 26257] LL And: emerging superhumps?
by Taichi Kato 18 Sep '21

18 Sep '21

LL And: emerging superhumps? Crimean Astrophys. Obs. team and Kiyota-san reported observations. (Tonny Vanmunster has sent a run, but it is not processed yet. This set will be reflected on further reports). A period analysis yielded 0.05698(4) d. This could be a signature of emerging superhumps. The amplitude is, however, very low and more observations are definitely needed for a secure identification.

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[vsnet-alert 26256] ASASSN-19ax: possible superhump
by Taichi Kato 18 Sep '21

18 Sep '21

ASASSN-19ax: possible superhump Kiyota-san reported observations. The object showed 0.3-mag variation resembling a superhump. The length of observation was not sufficient to record a full cycle. The period (if the variation is periodic) appears to be longer than 2 hr and the object could be an SU UMa star above the period gap. Further observations are strongly encouraged.

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[vsnet-alert 26199] OT J215818.5+241925 in Outburst
by Gary Poyner 17 Sep '21

17 Sep '21

The UGSU star OT J215818.5+241925 (PNV J21581852+2419246) is in outburst. The first detected since September 2018... September 03.940 14.903CV Open University COAST regards, Gary -- ------------------------------------------------------ Gary Poyner FRAS garypoyner(a)gmail.com www.variablestars.co.uk

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[vsnet-alert 26254] ASASSN-19ax possible superoutburst
by Taichi Kato 17 Sep '21

17 Sep '21

ASASSN-19ax possible superoutburst Suspected type from ZTF + ASAS-SN data. YYYYMMDD(UT) mag observer 20210906.9583 <142 (Eddy Muyllaert) 20210908.9069 <142 (Eddy Muyllaert) 20210909.9368 <142 (Eddy Muyllaert) 20210910.9194 128 (Eddy Muyllaert) 20210911.8451 127 (Eddy Muyllaert) 20210911.883 12.73C (Gary Poyner) 20210915.9076 128 (Eddy Muyllaert)

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vsnet-alert September 2021