[vsnet-outburst 31701] ASASSN-26ew: new SU UMa-type dwarf nova, possibly WZ Sge-type
ASASSN-26ew: new SU UMa-type dwarf nova, possibly WZ Sge-type ASASSN reported the discovery of ASASSN-26ew at 14.73 mag on 2026-08-13.82 UT. The archival ASASSN light curve shows that this had the outburst maximum on 2026-08-07.9 UT around 13.7 mag. The likely counterpart is the Bj=22.2 mag star in the GSC v2.4.2 catalogue; thus the outburst amplitude is ~8.5 mag. https://vsx.aavso.org/index.php?view=detail.top&oid=10875981 The SAAO Lesedi telescope observed ASASSN-26ew on 2026-08-18 and 2026-08-19. The light curve shows clear ordinary superhumps with a period of 0.05677(3) d and an amplitude of 0.15 mag. Thus ASASSN-26ew is a new SU UMa-type dwarf nova. Given its short superhump period and large outburst amplitude, this is a good candidate for a WZ Sge-type dwarf nova. The optical spectrum, also observed with the Lesedi telescope on 2026-08-18 UT, shows the Balmer absorption lines and superposed narrow emission core in Hα. Follow-up observations are encouraged. Best regards, Yusuke -- ---------------------------------------------- Yusuke TAMPO / 反保 雄介 Postdoc fellow South African Astronomical Observatory / University of Cape Town EMAIL: tampo@kusastro.kyoto-u.ac.jp ALT. EMAIL: yusuke@saao.ac.za ----------------------------------------------
ASASSN-26ew: updated superhump period Josch Hambsch has reported further time-resolved observations. The updated superhump period is 0.05633(2) d (aliases still possible). Best regards, Yusuke 2026年8月20日(木) 12:48 Yusuke Tampo <tampo@kusastro.kyoto-u.ac.jp>:
ASASSN-26ew: new SU UMa-type dwarf nova, possibly WZ Sge-type
ASASSN reported the discovery of ASASSN-26ew at 14.73 mag on 2026-08-13.82 UT. The archival ASASSN light curve shows that this had the outburst maximum on 2026-08-07.9 UT around 13.7 mag. The likely counterpart is the Bj=22.2 mag star in the GSC v2.4.2 catalogue; thus the outburst amplitude is ~8.5 mag. https://vsx.aavso.org/index.php?view=detail.top&oid=10875981
The SAAO Lesedi telescope observed ASASSN-26ew on 2026-08-18 and 2026-08-19. The light curve shows clear ordinary superhumps with a period of 0.05677(3) d and an amplitude of 0.15 mag. Thus ASASSN-26ew is a new SU UMa-type dwarf nova. Given its short superhump period and large outburst amplitude, this is a good candidate for a WZ Sge-type dwarf nova.
The optical spectrum, also observed with the Lesedi telescope on 2026-08-18 UT, shows the Balmer absorption lines and superposed narrow emission core in Hα.
Follow-up observations are encouraged.
Best regards, Yusuke
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Yusuke TAMPO / 反保 雄介 Postdoc fellow South African Astronomical Observatory / University of Cape Town EMAIL: tampo@kusastro.kyoto-u.ac.jp ALT. EMAIL: yusuke@saao.ac.za
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-- ---------------------------------------------- Yusuke TAMPO / 反保 雄介 Postdoc fellow South African Astronomical Observatory / University of Cape Town EMAIL: tampo@kusastro.kyoto-u.ac.jp ALT. EMAIL: yusuke@saao.ac.za ----------------------------------------------
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Yusuke Tampo