April 2024 - vsnet-alert - ooruri.kusastro.kyoto-u.ac.jp

[vsnet-alert 27998] Call for monitoring of SS Cyg
by Daisaku NOGAMI 10 Jun '24

10 Jun '24

Dear colleagues, We would like to call for dense monitoring of SS Cyg for coming tens of days. X-ray observations by the new X-ray telescope XRISM (PI: Manabu Ishida) will be scheduled based on optical detection of the next outburst. The SS Cyg observation window with XRISM will open on April 14. We would be thankful, if the VSNET observers would monitor SS Cyg more than usual and timely report outburst detection, say brighter than V=11.0. Best regards, Daisaku Nogami --- Daisaku NOGAMI <nogami(a)kusastro.kyoto-u.ac.jp>

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[vsnet-alert 28002] ASASSN-19rx: started very slow long outburst?
by Kojiguchi 30 Apr '24

30 Apr '24

ASASSN-19rx: started very slow long outburst? According to ZTF alerts, this object is slightly brighter than its quiescence in now. This object might started an outburst. Eclipse. Porb = 2.47d. Outburst cycle: about 5 years Outburst duration: about 1 year ephemeris of primary/secondary eclipses calculated (based on ephemeris in Junpei Ito's master thesis): 2024-04-30T19:55:22 (primary) 2024-05-02T01:35:50 (secondary) 2024-05-03T07:16:19 (primary) 2024-05-04T12:56:47 (secondary) 2024-05-05T18:37:16 (primary) 2024-05-07T00:17:44 (secondary) 2024-05-08T05:58:12 (primary) 2024-05-09T11:38:41 (secondary) 2024-05-10T17:19:09 (primary) 2024-05-11T22:59:38 (secondary) 2024-05-13T04:40:06 (primary) 2024-05-14T10:20:34 (secondary) 2024-05-15T16:01:03 (primary) 2024-05-16T21:41:31 (secondary) 2024-05-18T03:22:00 (primary) 2024-05-19T09:02:28 (secondary) 2024-05-20T14:42:57 (primary) 2024-05-21T20:23:25 (secondary) See also: vsnet-alert 23931, 23451, 23460, 23466

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[vsnet-alert 28000] Follow-up CCD observation of SN 2024ggi in NGC 3621
by Filipp Romanov 15 Apr '24

15 Apr '24

I observed SN 2024ggi in NGC 3621 remotely at iTelescope.Net T32 (0.43-m f/6.8 reflector + CCD) at Siding Spring Observatory, Australia, on 2024-04-11. 180-sec. image with V filter was obtained with midtime 14:33:30 UT and 180-sec. image with Ic filter was obtained with midtime 14:37:23 UT. I measured the position (J2000.0) of the supernova: 11:18:22.091 -32:50:15.34. I measured the magnitude of it: V = 16.220 +/- 0.024 from comparison to magnitudes of nearby stars from APASS DR9 catalogue (Henden et al., 2016). Color image available here: https://www.flickr.com/photos/filipp-romanov/53649145565 SN 2024ggi 20240411.60660 16.220V RFD 0.024 F. D. Romanov (AAVSO).

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[vsnet-alert 27999] ASASSN-24cg (aka Gaia DR3 4378710224740797312): new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 04 Apr '24

04 Apr '24

Dear colleagues, I have just finished analysing my unfiltered CCD observations of ASASSN-24cg (aka Gaia DR3 4378710224740797312 and TCP J16454549-0257144) obtained on 2024, Apr 03/04 at CBA Extremadura Observatory using a 0.40-m f/5.1 telescope and SX-46 CCD camera, under clear skies. The resulting light curve clearly shows the presence of superhumps with an amplitude of 0.34 mag, establishing ASASSN-24cg as a new SU UMa-type dwarf nova. A period analysis, using the ANOVA, Lomb-Scargle, Lomb-Scargle GLS and PDM methods (Peranso 3.0) yields a combined superhump period of 0.0613 +/- 0.0007d. The object was at mag CV = 13.5 on Apr 4th. Image calibration and photometry were done using a beta version of Phoranso. I will send my observations to AAVSO, CBA and VSNET for further analysis. Best regards Tonny With kind regards, Tonny --- Tonny Vanmunster CBA Belgium Observatory CBA Extremadura Observatory http://www.cbabelgium.co <http://www.cbabelgium.com/> m PERANSO : The Light Curve and Period Analysis Software http://www.peranso.co <http://www.peranso.com/> m PHORANSO: Photometric Reduction and Analysis Software *** NEW - COMING SOON *** http://www.phoranso.com <http://www.phoranso.com/>

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