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

[vsnet-alert 28087] Two bright nova candidates in M31
by FIDRICH Robert 08 Jul '25

08 Jul '25

Dear Friends, I managed to discover two bright nova candidates in M31 in the las few days: *Vend60 (AT 2025qdc = M31N 2025-07a)* https://vendegcsillagkereso.blogspot.com/2025/07/vend60-possible-nova-in-m3… https://www.wis-tns.org/object/2025qdc This star got significantly brighter over the weekend (~16.5-17.0 magnitudes) See my recent photos: https://vendegcsillagkereso.blogspot.com/2025/07/vend-60-uj-novajelolt-az-a… *Vend61 (AT 2025qmf)* https://vendegcsillagkereso.blogspot.com/2025/07/vend61-possible-nova-near-… https://www.wis-tns.org/object/2025qmf Located 2178" west and 281" south of the center of M31. (Source: Extracalactic Novae page, Rochesterastronomy) Follow-up photometry, spectroscopy of both nova candidates and precize astrometry of AT 2025qmf urgently needed. Clear skies, Robert

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[vsnet-alert 28086] ASASSN-25cn
by 保家大将 07 Jul '25

07 Jul '25

ASASSN-25cn : new SU UMa-type dwarf nova,and possibly WZ Sge-type ASAS-SN discovered ASASSN-25cn on 2025-06-15.77 UTC at g=13.5 mag. According to VSX, this object's quiescence magnitude is B~22.0 thus the outburst amplitude is ~8.5 mag. VSX : Detail for ASASSN-25cn Josch Hambsch, Berto Monard, Itoh-san reported the time-resolved observations. These light curves (after 2025-6-26 UTC) show ordinary superhumps with an amplitude of ~0.2 mag and a period of 0.0567233(294)d. Hence, ASASSN-25cn is a new SU UMa-type dwarf nova. Due to the sparse coverage before June 19, we cannot judge if ASASSN-25cn showed early superhumps. Given the large outburst amplitude and short superhump period, it can be a WZ Sge-type dwarf nova. Best regards, Hiromasa

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[vsnet-alert 28084] ASASSN-25cu: new SU UMa-type dwarf nova
by tonny.vanmunster＠gmail.com 29 Jun '25

29 Jun '25

Dear colleagues, I have just completed the analysis of my unfiltered CCD observations of ASASSN-25cu, obtained on Jun 27/28 and 28/29, 2025 at CBA Belgium Observatory. The data was collected using a 0.40-m f/10.0 telescope and QHY-268M CMOS camera under clear skies. The light curve clearly reveals the presence of regular superhumps with an amplitude of 0.25 mag, establishing ASASSN-25cu as a new SU UMa-type dwarf nova. A period analysis, using the ANOVA, Lomb-Scargle, Generalized-Lomb-Scargle and PDM methods (Peranso 3.1) yields a combined superhump period of 0.0536 +/- 0.0014d. The object was measured at mag CV = 15.7 on Jun 29th. Image calibration and photometry were performed using the latest release of Phoranso. Further observations are encouraged to refine the superhump period. 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 28083] Re: [baavss-alert] PNV J10251200-5331109: possible nova in Vela at 5.7 mag
by walcom77 25 Jun '25

25 Jun '25

Hi All, Following the posting on the Central Bureau's Transient Object Confirmation Page regarding a possible nova in Vela (TOCP Designation: TCP PNV J10251200-5331109), we performed follow-up observations of this object using a 0.35-m f/3.0 reflector telescope equipped with a CMOS camera, located near Perth, Western Australia, and operated by SPACEFLUX company. In images taken on June 25.57, 2025, we confirm the presence of an optical counterpart with an unfiltered CMOS magnitude of approximately +7 (this value is a lower limit due to strong saturation in the 1-second exposure, indicating the object is likely significantly brighter), at coordinates R.A. = 10 25 13.89, Decl. = -53 31 21.0 (equinox 2000.0; astrometry based on Gaia DR2 catalogue reference stars). An animation showing a comparison between our image and an archive POSS plate (1996) is available at the following url: https://tinyurl.com/novavela Kind Regards, Ernesto Guido & Marco Rocchetto (SPACEFLUX) On Wed, Jun 25, 2025 at 3:50 PM Gary Poyner via groups.io <garypoyner=gmail.com(a)groups.io> wrote: > > ---------- Forwarded message --------- > From: Yusuke Tampo <tampo(a)kusastro.kyoto-u.ac.jp> > Date: Wed, 25 Jun 2025 at 14:43 > Subject: [vsnet-alert 28082] PNV J10251200-5331109: possible nova in Vela at 5.7 mag > To: vsnet-alert(a)ooruri.kusastro.kyoto-u.ac.jp <vsnet-alert(a)ooruri.kusastro.kyoto-u.ac.jp> > > > PNV J10251200-5331109: possible nova in Vela at 5.7 mag > > In TOCP, John Seach (and independently Andrew Pearce) reported the possible > nova PNV J10251200-5331109 in Vela at 5.7 mag on 2025 06 25, possibly > another naked-eye nova! > http://www.cbat.eps.harvard.edu/unconf/followups/J10251200-5331109.html > > Classification spectroscopy is highly encouraged. > Unfortunately, the weather in Sutherland seems bad for the next few days. > > 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 > > ---------------------------------------------- > > > _._,_._,_ > ________________________________ > Groups.io Links: > > You receive all messages sent to this group. > > View/Reply Online (#1134) | Reply to Group | Reply to Sender | Mute This Topic | New Topic > Your Subscription | Contact Group Owner | Unsubscribe [walcom77(a)gmail.com] > > _._,_._,_

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[vsnet-alert 28082] PNV J10251200-5331109: possible nova in Vela at 5.7 mag
by Yusuke Tampo 25 Jun '25

25 Jun '25

PNV J10251200-5331109: possible nova in Vela at 5.7 mag In TOCP, John Seach (and independently Andrew Pearce) reported the possible nova PNV J10251200-5331109 in Vela at 5.7 mag on 2025 06 25, possibly another naked-eye nova! http://www.cbat.eps.harvard.edu/unconf/followups/J10251200-5331109.html Classification spectroscopy is highly encouraged. Unfortunately, the weather in Sutherland seems bad for the next few days. 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 28081] ASASSN-25ci
by 保家大将 20 Jun '25

20 Jun '25

ASASSN-25ci: new SU UMa-type dwarf nova,and possibly WZ Sge-type ASAS-SN discovered ASASSN-25ci on 2025-06-5.31 UTC at g=13.51 mag. According to VSX, this object's quiescence magnitude is B~21.0 thus the outburst amplitude is ~7.5 mag. https://vsx.aavso.org/index.php?view=detail.top&oid=10848701 Berto Monard and Josch Hambsch reported the time-resolved observations. These light curves (after 2025-6-11 UTC) show ordinary superhumps with an amplitude of ~0.3 mag and a period of 0.0535(1)d. Hence, ASASSN-25ci is a new SU UMa-type dwarf nova. Due to the sparse coverage before June 11, we cannot judge if ASASSN-25ci showed early superhumps. Given the large outburst amplitude and short superhump period, it can be a WZ Sge-type dwarf nova. Best regards, Hiromasa kyoto university hiromasa hoke / 保家大将 email: hoke(a)kusastro.kyoto-u.ac.jp

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[vsnet-alert 28074] ASASSN-25cm - 8.7 mag transient in Lupus
by Kirill Sokolovsky 17 Jun '25

17 Jun '25

The ASAS-SN team has posted a bright transient on the TNS: ASASSN-25cm = AT 2025nlr 15:08:03.274 -40:08:29.58 g=8.7 https://www.wis-tns.org/object/2025nlr with the following comment: "Very bright, young transient, possibly a Galactic Nova; photometry likely uncertain as the object is close to/above saturation limit". The extinction in this direction is relatively low A(V) = 0.345, so a typical classical nova peaking at absolute magnitude M_V= -7.0 at 8 kpc distance would rise to V=7.9. Confirmation imaging, astrometry, filter photometry and classification spectroscopy are all highly desirable. Best wishes, Kirill

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[vsnet-alert 28076] Re: ASASSN-25cm - 8.7 mag transient in Lupus
by Mohammad Odeh 15 Jun '25

15 Jun '25

Greetings, Attached are the results few minutes ago! It is very bright now! Please notice that each measurement is a stack of 14 or 15 frames. I'm observing using three filters Ic, V, and B. I've uploaded my results to AAVSO. ********************************************************** Best Regards Mohammad Shawkat Odeh IAU Active Member Director of the International Astronomical Center (IAC) Al Khatim Observatory (IAU MPC code M44) Abu Dhabi, UAE <mailto:modeh@astronomycenter.net> modeh(a)astronomycenter.net <http://www.astronomycenter.net/> http://www.astronomycenter.net/ **********************************************************

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[vsnet-alert 28073] PNV J06302516-6955014: classical nova
by Yusuke Tampo 06 Jun '25

06 Jun '25

PNV J06302516-6955014: classical nova I reported the optical spectrum of PNV J06302516-6955014 to ATel and classified it as a classical nova. https://www.astronomerstelegram.org/?read=17224 ASAS-SN also detected its rise on 2025-06-04. https://asas-sn.osu.edu/sky-patrol/coordinate/0f0a542e-3695-45e3-95d4-cabe9… 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 28072] TCP J20131357+1154031: new SU UMa-type dwarf nova, possibly WZ Sge-type
by Yusuke Tampo 03 Jun '25

03 Jun '25

TCP J20131357+1154031: new SU UMa-type dwarf nova, possibly WZ Sge-type K. Itagaki discovered TCP J20131357+1154031 on 2025-05-19 UTC at 14.7 mag (unfiltered). The outburst amplitude is ~8.4 mag. https://www.aavso.org/vsx/index.php?view=detail.top&oid=10848625 SAAO/Lesedi telescope, Josch Hambsch, and Sano-san have reported the time-resolved observations. Josch's observations after 28 May show single-peaked variation with a period of 0.05797(6) d, likely an ordinary superhump. No clear modulations were presented before this. Thus TCP J20131357+1154031 is a new SU UMa-type dwarf nova and a good candidate for a WZ Sge-type dwarf nova, given its late appearance of ordinary superhumps. 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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