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

[vsnet-alert 28049] TCP J07222683+6220548: AM CVn star showing a superoutburst
by Yusuke Tampo 28 Feb '25

28 Feb '25

TCP J07222683+6220548: AM CVn star showing a superoutburst The time-resolved observations of TCP J07222683+6220548 aka ZTF25aacfjde have been repoted by Itoh-san, Sano-san, Josch Hambsch and Tamás Tordai. This object showed a 4-mag dip in the middle of the outburst, and time-resolved observations by Itoh-san after the recovery from this dip detected single-peaked variations with a period of 0.03256(2) d, likely an ordinary superhump. Thus TCP J07222683+6220548 is a new AM CVn star showing a superoutburst. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow 反保雄介 Yusuke TAMPO MAIL: tampo(a)kusastro.kyoto-u.ac.jp MAIL: yusuke(a)saao.ac.za ----------------------------------------------

1 0

[vsnet-alert 28048] V748 Hya outburst
by Rod Stubbings 23 Feb '25

23 Feb '25

The UGWZ star V748 Hya in bright outburst. HYAV748 250223.517 120 Stu.RASNZ -- 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/

1 0

[vsnet-alert 28047] ASASSN-25ao
by Berto Monard 05 Feb '25

05 Feb '25

Hello, ASASSN-25ao, an outbursting blue object was observed at CBA-KKO on 3 and 4 Feb 2026. The object faded from an average of 15.85 to 16.16 CR (unfiltered magnitudes) over that period. The light curves showed a modulation hinting at a main period around 0.12d and a strong secondary period of 0.030d +/- 0.0005d, derived from GLS and PDM methods in Peranso. Further observations are planned for Friday 7 Feb, when skies will be clear again. Berto Monard / CBA KKO Calitzdorp, South Africa

1 0

[vsnet-alert 28046] V4141Sgr outburst
by Tadashi Kojima 03 Feb '25

03 Feb '25

object YYYYMMDD(UT) mag V4141Sgr 20250203.8359 13.7c Observer: Tadashi Kojima (Tsumagoi,Gunma, Japan) Instruments:fl=300mm lens +Canon EOS6D digital camera

1 0

[vsnet-alert 28041] TCP J04272195-2528038; possibly a new AM CVn star in outburst?
by Yusuke Tampo 02 Feb '25

02 Feb '25

TCP J04272195-2528038; possibly a new AM CVn star in outburst? TCP J04272195-2528038 was discovered by Y. Nakamura on 2025-01-09.4837 UT at 14.2 mag. The quiescence counterpart is g_PS1=21.09(5) mag, thus outburst amplitude is ~7 mag. http://www.cbat.eps.harvard.edu/unconf/followups/J04272195-2528038.html https://www.aavso.org/vsx/index.php?view=detail.top&oid=2391199 Itoh-san and myself using the SAAO/Lesedi telescope have reported the time-resolved observations. The SAAO data shows a possible double-peaked modulation with a period of ~42.6 min. In addition, the optical spectrum I obtained with the 1.9m telescope at the SAAO shows only the He I absorption lines, lacking any significant Balmer emission/absorption lines. Further observations are encouraged to establish its classification and determine the variation period. Best regards, Yusuke -- ---------------------------------------------- South African Astronomical Observatory, Postdoc fellow 反保雄介 Yusuke TAMPO MAIL: tampo(a)kusastro.kyoto-u.ac.jp MAIL: yusuke(a)saao.ac.za ----------------------------------------------

2 4