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

[vsnet-alert 26338] 1RXS J063214.8+253620 (UG) first outburst since 2012
by Kirill Sokolovsky 08 Nov '21

08 Nov '21

Hi, The dwarf nova 1RXS J063214.8+253620 was found in outburst on the NMW survey images (135mm f/2.0 lens + unfiltered ST-8300M CCD): YYYYMMDD.D(UT) mag 20211020.9384 12.6CV The ASAS-SN lightcurve https://asas-sn.osu.edu/sky-patrol/coordinate/7272c442-c9b2-4ec3-b8a8-9780a… suggests the outburst started on 2021-10-19 and this is the first outburst since the discovery of this dwarf nova in 2012. The ASAS-SN data also suggest the presence of periodic modulation in minimum light. The quiescent K2 lightcurve of 1RXS J063214.8+253620 was modeled by https://ui.adsabs.harvard.edu/abs/2018AJ....156..153D/abstract VSX record for 1RXS J063214.8+253620: https://www.aavso.org/vsx/index.php?view=detail.top&oid=276839 Some of the previous messages on vsnet-alert discussing the 2012 outburst: http://ooruri.kusastro.kyoto-u.ac.jp/mailarchive/vsnet-alert/14158 http://ooruri.kusastro.kyoto-u.ac.jp/mailarchive/vsnet-alert/14171 http://ooruri.kusastro.kyoto-u.ac.jp/mailarchive/vsnet-alert/14172 Best wishes, Kirill Sokolovsky, Stanislav Korotkiy, Olga Smolyankina

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[vsnet-alert 26370] Gaia21efs: likely CV (dwarf nova?)
by Taichi Kato 01 Nov '21

01 Nov '21

Gaia21efs: likely CV (dwarf nova?) Tonny Vanmunster reported observations. The data show 0.15 mag variations (flickering or part of early superhumps?). The object is thus unlikely a microlensing, but likely a CV. Spectroscopy is encouraged.

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[vsnet-alert 26369] OT J002656.6+284933 superhumps
by Taichi Kato 30 Oct '21

30 Oct '21

OT J002656.6+284933 superhumps (=CSS101212:002657+284933) Sano-san and Tamas Tordai have reported observations. 0.3-mag superhumps are clearly present.

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[vsnet-alert 26368] OT J002656.6+284933 superoutburst
by Taichi Kato 29 Oct '21

29 Oct '21

OT J002656.6+284933 superoutburst (=CSS101212:002657+284933) This object is known as an SU UMa star above the period gap with multiple rebrightenings. The last outburst was recorded in 2016. https://ui.adsabs.harvard.edu/abs/2017PASJ...69L...4K/abstract YYYYMMDD(UT) mag observer 20211013.6632 <159c (Yutaka Maeda) 20211014.6574 <167c (Yutaka Maeda) 20211015.6572 <165c (Yutaka Maeda) 20211017.6568 <158c (Yutaka Maeda) 20211023.5999 154:c (Yutaka Maeda) 20211025.5847 153cG (Yutaka Maeda) 20211026.5832 152:cG (Yutaka Maeda) 20211027.5983 153:cG (Yutaka Maeda)

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[vsnet-alert 26367] OGLE-MC-DN-0008: new SU UMa-type dwarf nova
by Taichi Kato 29 Oct '21

29 Oct '21

OGLE-MC-DN-0008: new SU UMa-type dwarf nova Josch Hambsch has reported observations on two nights. The object shows 0.17-mag superhumps with a period of 0.06056(8) d.

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[vsnet-alert 26366] ASASSN-21tr: superhump period
by Taichi Kato 28 Oct '21

28 Oct '21

ASASSN-21tr: superhump period Tonny Vanmunster, Tamas Tordai and Itoh-san have reported observations. The superhump period since Oct. 25 is 0.0666(2) d. The amplitude is still small (0.06 mag) and they are most likely stage A superhumps.

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[vsnet-alert 26365] XM78HT: regular superhumps
by Taichi Kato 28 Oct '21

28 Oct '21

XM78HT: regular superhumps The most recent data by Kyoto U. team on Oct. 26 detected clear ordinary superhumps. The superhumps started growing on Oct. 25 (Vihorlat Obs. team). The current period (stage A) is 0.05596(8) d.

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[vsnet-alert 26364] IPHAS J184326.48+060800.9 (eclipsing polar) high state
by Taichi Kato 27 Oct '21

27 Oct '21

IPHAS J184326.48+060800.9 (eclipsing polar) high state http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia21ewn/ High state of this polar has not been seen in the ZTF data. First time in recent years. See [vsnet-chat 8874] (Sep. 22) about the nature of this object.

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[vsnet-alert 26363] ASASSN-19ty: new SU UMa-type dwarf nova
by Taichi Kato 27 Oct '21

27 Oct '21

ASASSN-19ty: new SU UMa-type dwarf nova Josch Hambsch has reported observations. This object showed 0.15-mag superhump with a period of about 0.056 d.

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[vsnet-alert 26362] ASASSN-21tr: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 27 Oct '21

27 Oct '21

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 --- 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 October 2021