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[vsnet-alert 28114] 1eRASS J072044.9-402838 = PNV J07204545-4028357 = ASASSN-25ee: new SU UMa-type dwarf nova, likely WZ Sge-type
by Yusuke Tampo 05 Nov '25

05 Nov '25

1eRASS J072044.9-402838 = PNV J07204545-4028357 = ASASSN-25ee: new SU UMa-type dwarf nova, likely WZ Sge-type 1eRASS J072044.9-402838 was originally identified as a CV candidate in Rodriguez et al. (2025), G = 19.2 mag at ~267 pc, hence its absolute magnitude of ~12 mag. https://vsx.aavso.org/index.php?view=detail.top&oid=10868116 https://ui.adsabs.harvard.edu/abs/2025PASP..137a4201R/abstract ASASSN and John Seach discovered its 2025 outburst, peaking at ~11.0 mag around 20th October. https://www.astronomy.ohio-state.edu/asassn/transients.html http://www.cbat.eps.harvard.edu/unconf/followups/J07204545-4028357.html We, the SAAO team, obtained the time-resolved photometries and a snapshot spectrum of 1eRASS J072044.9-402838 on 3rd Nov. The light curve shows likely superhumps with a rough period of ~0.059 d. The spectrum shows Balmer absorption lines from the accretion disk and a superposed narrow emission component in Hα. Hence, 1eRASS J072044.9-402838 is now confirmed as (at least) a SU UMa-type dwarf nova, and probably a WZ Sge-type dwarf nova, considering its large outburst amplitude, long outburst duration, and short superhump period. Further time-resolved observations are encouraged to establish its superhump period and changes. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow Yusuke TAMPO / 反保雄介 EMAIL: tampo(a)kusastro.kyoto-u.ac.jp ALT. EMAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-alert 28117] Possible bright missed supernova in ESO 157-27 galaxy
by Filipp Romanov 04 Nov '25

04 Nov '25

I found an interesting object when I blinked images from the DSS Plate Finder https://archive.stsci.edu/cgi-bin/dss_plate_finder with photos obtained on 2025-11-03 at the remote telescope T75 of iTelescope.Net in Chile. This year I discovered SN 2025umq (Type Ia supernova https://ui.adsabs.harvard.edu/abs/2025ATel17361....1R/ in the galaxy SDSS J004819.14+075856.8) this way, but this time the object was not in new photographs, but in archival ones. I found a possible bright missed supernova in the ESO 157-27 galaxy on the POSS-II F plate (1994-12-28 12:45:00, exposure time 70 minutes). I measured magnitude R = 12.3 compared to the R magnitudes of nearby stars from the ATLAS catalog (Tonry, et al., 2018). My measured J2000.0 position: 04:25:32.31 -56:51:20.09. GSC2.3 position = 04:25:32.2 -56:51:21.8; GSC2.3 magnitude R = 10.02; name GSC2.3 S12G005521. Now this is AT 1994au https://www.wis-tns.org/object/1994au (in the TNS). For comparison: 1994-12-28 DSS Red plate and image from DESI Legacy Surveys: https://www.wis-tns.org/system/files/uploaded/F.%20D.%20Romanov/tns_1994au_… No nearby minor planets found via Minor Planet Checker, there are no similar supernovae in the list http://www.cbat.eps.harvard.edu/lists/Supernovae.html and in the Transient Name Server. It does not look like a defect in the plate because the rays are similar to those of other stars. There are no objects nearby in other images from other years. I have previously found similar astronomical transients - possible missed supernovae AT 1991bm in the galaxy UGC 11180 and AT 1992bw in the galaxy UGC 43 - in the images from the DSS Plate Finder (I mentioned this in my paper: https://ui.adsabs.harvard.edu/abs/2022arXiv221212543R ), like the possible dwarf nova Romanov V1 (on two POSS plates for 1958, more details about this: https://ui.adsabs.harvard.edu/abs/2018OEJV..190....1R/ ). This is likely one of the brightest possible missed supernovae. Filipp Romanov (AAVSO).

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[vsnet-alert 28115] TCP J05415572-2308340: new WZ Sge-type dwarf nova
by Yusuke Tampo 04 Nov '25

04 Nov '25

TCP J05415572-2308340: new WZ Sge-type dwarf nova The NMW survey discovered TCP J05415572-2308340 at 13.2 mag on 16 Oct. The counterpart is Gaia EDR3 2963574610161432960 G= 20.65(1) mag. https://vsx.aavso.org/index.php?view=detail.top&oid=10868112 http://www.cbat.eps.harvard.edu/unconf/followups/J05415572-2308340.html Josch Hambsh and Itoh-san have reported the time-resolved observations of TCP J05415572-2308340. After 23 Oct 2025, this shows the single-peaked superhumps with a mean period of 0.05496(2) d and an amplitude of 0.08 mag. Before this epoch, there were no clear modulations. Thus, this long waiting time before the appearance of ordinary superhumps, together with a large outburst amplitude and long outburst duration, suggests that TCP J05415572-2308340 is a new WZ Sge-type dwarf nova. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow Yusuke TAMPO / 反保雄介 EMAIL: tampo(a)kusastro.kyoto-u.ac.jp ALT. EMAIL: yusuke(a)saao.ac.za ----------------------------------------------

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[vsnet-alert 28116] Possible bright missed supernova in ESO 157-27 galaxy
by Filipp Romanov 03 Nov '25

03 Nov '25

Hello to all! Today I found an interesting object when I blinked images from the DSS Plate Finder https://archive.stsci.edu/cgi-bin/dss_plate_finder with photos obtained on the remote telescope T75 of iTelescope.Net in Chile. This year I discovered SN 2025umq (Type Ia supernova https://ui.adsabs.harvard.edu/abs/2025ATel17361....1R/ in the galaxy SDSS J004819.14+075856.8) this way, but this time the object was not in new photographs, but in archival ones. I found a possible bright missed supernova in the ESO 157-27 galaxy on the POSS-II F plate (1994-12-28). I measured magnitude R = 12.3 compared to the R magnitudes of nearby stars from the ATLAS catalog (Tonry, et al., 2018). My measured J2000.0 position: 04:25:32.31 -56:51:20.09. GSC2.3 position = 04:25:32.2 -56:51:21.8; GSC2.3 magnitude R = 10.02; name GSC2.3 S12G005521. Now this is AT 1994au https://www.wis-tns.org/object/1994au (in the TNS). For comparison: 1994-12-28 DSS Red plate and image from DESI Legacy Surveys: https://www.wis-tns.org/system/files/uploaded/F.%20D.%20Romanov/tns_1994au_… No nearby minor planets found via Minor Planet Checker, there are no similar supernovae in the list http://www.cbat.eps.harvard.edu/lists/Supernovae.html and in the Transient Name Server. It does not look like a defect in the plate because the rays are similar to those of other stars. I have previously found similar astronomical transients - possible missed supernovae AT 1991bm in the galaxy UGC 11180 and AT 1992bw in the galaxy UGC 43 - in the images from the DSS Plate Finder (I mentioned this in my paper: https://ui.adsabs.harvard.edu/abs/2022arXiv221212543R ), like the possible dwarf nova Romanov V1 (on two POSS plates for 1958, more details about this: https://ui.adsabs.harvard.edu/abs/2018OEJV..190....1R/ ). But this is likely one of the brightest possible missed supernovae. With best regards, Filipp Romanov (AAVSO).

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[vsnet-alert 28113] maintenance power outrage
by 保家大将 30 Oct '25

30 Oct '25

Dear, VSNET members, I'm Hiromasa Hoke, a master student of Kyoto University. I must inform you all that there will be a maintenance power outage for the Kyoto Univ. building on this weekend, so VSNET server must be shut down in advance. The shutdown is scheduled to occur around 16:00 JST on November 1st (UTC: 07:00), and the system is scheduled to be restored at around 11:30 JST (UTC: 02:30) on November 4th. Thank you for your cooperation. Hiromasa Hoke

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[vsnet-alert 28112] TCP J20522886+1637203: a likely new WZ Sge-type dwarf nova
by tonny.vanmunster＠gmail.com 18 Oct '25

18 Oct '25

Dear colleagues, TCP J20522886+1637203 was discovered by XOSS (Xingming Observatory Sky Survey) on 2025 Oct 08.6 at mag 12.73 CV. The quiescent counterpart is a 22.1 r mag object, implying an outburst amplitude of ~9 mag. I have been observing this object on a very regular basis since Oct 08th with no periodic modulations visible in the light curves - until last night (Oct 17/18). I have just completed the analysis of my unfiltered CCD observations of TCP J20522886+1637203, obtained on 2025 Oct 17/18 at CBA Extremadura Observatory. The data were acquired under clear skies with a 0.40-m f/5.1 telescope and a Moravian G2-4000 CCD. The light curve now shows clear ordinary superhumps with an amplitude of 0.20 mag. Given their late onset (9 dyas after detection) and the large outburst amplitude, we conclude that TCP J20522886+1637203 is a new WZ Sge-type dwarf nova. A period analysis, using ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0567 +/- 0.0004d. The object was measured at mag CV = 15.0 on Oct 18th. Image calibration and photometry were performed with the latest release of Phoranso, which enabled simultaneous photometry of several additional variable stars within the same frames. Continued monitoring is strongly encouraged to study the superhump profile and evolution. I will submit my observations to AAVSO, CBA and VSNET for further analysis. 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 http://www.phoranso.com <http://www.phoranso.com/>

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[vsnet-alert 28111] TCP J03173646+7459318: a likely new WZ Sge-type dwarf nova
by tonny.vanmunster＠gmail.com 23 Sep '25

23 Sep '25

Dear colleagues, TCP J03173646+7459318 was discovered by XOSS (Xingming Observatory Sky Survey) on 2025 Sep 21.8 at mag 13.78C. The quiescent counterpart is a 20.9 V mag object, implying an outburst amplitude of ~8 mag. I have just completed the analysis of my unfiltered CCD observations of TCP J03173646+7459318, obtained on 2025 Sep 22/23 at CBA Extremadura Observatory. The data were acquired under clear skies with a 0.40-m f/5.1 telescope and a Moravian G2-4000 CCD. The light curve clearly reveals double-peaked modulations consistent with early superhumps, with an amplitude of 0.09 mag. A period analysis, using ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0600 +/- 0.0006d. The object was measured at mag CV = 13.6 on Sep 23rd. Image calibration and photometry were performed with the latest release of Phoranso, which enabled simultaneous photometry of several additional variable stars within the same frames. These findings strongly suggest that TCP J03173646+7459318 is a new WZ Sge-type dwarf nova. Continued monitoring is strongly encouraged to study the superhump profile and evolution. I will submit my observations to AAVSO, CBA and VSNET for further analysis. 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 http://www.phoranso.com <http://www.phoranso.com/>

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[vsnet-alert 28110] TCP J20143906+0352503: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 23 Sep '25

23 Sep '25

Dear colleagues, TCP J20143906+0352503 was discovered by XOSS (Xingming Observatory Sky Survey) on 2025 Sep 16.7 at mag 15.72C. The quiescent counterpart is possibly a 21.1 V mag star 2" to the W, implying an outburst amplitude of ~5 mag. I have just completed the analysis of my unfiltered CCD observations of TCP J20143906+0352503, obtained on 2025 Sep 22/23 at CBA Extremadura Observatory. The data were acquired under clear skies with a 0.40-m f/5.1 telescope and a Moravian G2-4000 CCD. The light curve clearly exhibits superhump modulations with an amplitude of 0.25 mag. Period analysis with ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0641 +/- 0.0006d. The object was measured at mag CV = 16.4 on Sep 23rd. Additional observations obtained on earlier nights (e.g. Sep 21/22) also showed superhump activity; however, the data sets were too short due to clouds to permit a reliable period determination. Image calibration and photometry were performed with the latest release of Phoranso, which enabled simultaneous photometry of several additional variable stars within the same frames. These results establish TCP J20143906+0352503 as a new SU UMa-type dwarf nova. Follow-up observations are encouraged. I will submit my observations to AAVSO, CBA and VSNET for further analysis. 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 http://www.phoranso.com <http://www.phoranso.com/>

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[vsnet-alert 28109] Var Pic 2008 outburst!
by Rod Stubbings 18 Sep '25

18 Sep '25

Var Pic 2008 is currently in an outburst. I commenced observing this field in 2015; however, I have not recorded any detections to date. To my knowledge, I am not aware of any reported outbursts since its discovery in 2008. VAR PIC 2008 250917.640 <154 VAR PIC 2008 250918.674 134 Regards, Rod. -- Rod Stubbings Tetoora Road Observatory Victoria, Australia Honorary Associate member Astronomical Society of Australia Telescope: "Infinity" 22" f/3.8 stubbo(a)dcsi.net.au http://rodstubbingsobservatory.wordpress.com/

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[vsnet-alert 28108] ASASSN-25dt: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 12 Sep '25

12 Sep '25

Dear colleagues, ASASSN-25dt was discovered by the ASAS-SN Survey (Ohio State University) on 2025 Sep 05.3 at mag 14.5 V/g. The quiescent counterpart is a 20.1 g mag Pan-STARRS1 object, implying an outburst amplitude of ~5-6 mag. I have just completed the analysis of my unfiltered CCD observations of ASASSN-25dt, obtained on 2025 Sep 10/11 and Sep 11/12 at CBA Extremadura Observatory. The data were acquired under (mostly) clear skies with a 0.40-m f/5.1 telescope and a Moravian G2-4000 CCD. The Sep 10/11 light curve showed only irregular, small-amplitude variability. However, the Sep 11/12 light curve clearly exhibits superhump modulations with an amplitude of 0.27 mag. Period analysis with ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0605 +/- 0.0008d. The object was measured at mag CV = 15.9 on Sep 12th. Image calibration and photometry were carried out with the latest release of Phoranso. These results establish ASASSN-25dt as a new SU UMa-type dwarf nova. Follow-up observations are encouraged. I will submit my observations to AAVSO, CBA and VSNET for further analysis. 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 http://www.phoranso.com <http://www.phoranso.com/>

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