June 2025 - vsnet-alert - ooruri.kusastro.kyoto-u.ac.jp

[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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[vsnet-alert 28071] V905 Sco (LBV) Recent Brightening
by Peter Williams 03 Jun '25

03 Jun '25

The bright LBV star V905 Sco is classified as either SDOR or ACYG type. A fading of this star was reported in vsnet-alert 15793 of 04 June 2013. V905 Sco now appears to be recovering from that decline as shown by the below recent visual observations: SCOV905 20240613.434 69 WPX SCOV905 20240713.560 70 WPX SCOV905 20240722.471 69 WPX SCOV905 20240811.411 70 WPX SCOV905 20240904.409 69 WPX SCOV905 20241026.424 69 WPX SCOV905 20241027.452 68 WPX SCOV905 20250402.759 69 WPX SCOV905 20250503.506 69 WPX SCOV905 20250527.825 63 WPX SCOV905 20250531.392 63 WPX SCOV905 20250601.430 63 WPX Tks and regards Peter Williams Heathcote NSW 10x50mm binoculars

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[vsnet-alert 28070] ASASSN-25ce: new WZ Sge-type dwarf nova
by Yusuke Tampo 02 Jun '25

02 Jun '25

ASASSN-25ce: new WZ Sge-type dwarf nova ASAS-SN discovered ASASSN-25ce on 2025-05-28 UTC at 12.26 mag. The Gaia counterpart is G~20.7 mag thus the outburst amplitude is ~8.5 mag. The SAAO team and Berto Monard reported the time-resolved observations. These light curves show a double-peak modulation with an amplitude of ~0.1 mag and a period of ~0.05537(1) d. The 5-sec resolution observations by the SAAO/Lesedi telescope also show QPO-like modulation with 5--10 min. Hence, ASASSN-25ce is a new WZ Sge-type dwarf nova, possibly with a relatively higher inclination, while no clear eclipses are present. Further time-resolved observations are encouraged. 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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