TNS Classification Report No. 22346 [ 2025TNSCR4414....1T ]
Date Received (UTC): 2025-11-02 15:55:49 Sender: Kenta Taguchi
Group: None
Kenta Taguchi (Kyoto University), Keiichi Maeda (Kyoto University) report/s a classification of object: AT 2025abao
Type: LRN
Remarks: See ATel #17468. Our spectra taken by Seimei/KOOLS-IFU are dominated by a blue continuum. The emission line of Hα is prominently seen in both epochs (with Lorentzian FWHM ∼ 630 and 700 km/s on 2025-10-29.61 and 2025-10-31.72, respectively), while Hβ is only prominent on 2025-10-29.61 but has significantly weakened on 2025-10-31.72. The absorption line of NaI D is clearly seen in both epochs, suggesting that this object suffers from extinction. The evolution is similar to that of the luminous red nova AT 2019zhd, reported by Pastorello et al. (2021). From this similarity and the luminosity of the optical event, we propose that this event is likely a luminous red nova in M31, consistent with the common-envelope transient scenario of WNTR23bzdiq proposed by Karambelkar et al. (2025).
The following Classification spectrum was provided:
Obsdate: 2025-10-29 14:38:24
Instrument: Other
Telescope: Other
Remarks: See ATel #17468. A spectroscopic follow-up observation with KOOLS-IFU mounted on the 3.8-m Seimei telescope at Okayama Observatory of Kyoto University. The spectral resolution is ~ 500, and the wavelength coverage is 4100-8500 A.
Details of the object and its spectra can be viewed here: https://www.wis-tns.org/object/2025abao
Date Received (UTC): 2025-11-02 15:55:49 Sender: Kenta Taguchi
Group: None
Kenta Taguchi (Kyoto University), Keiichi Maeda (Kyoto University) report/s a classification of object: AT 2025abao
Type: LRN
Remarks: See ATel #17468. Our spectra taken by Seimei/KOOLS-IFU are dominated by a blue continuum. The emission line of Hα is prominently seen in both epochs (with Lorentzian FWHM ∼ 630 and 700 km/s on 2025-10-29.61 and 2025-10-31.72, respectively), while Hβ is only prominent on 2025-10-29.61 but has significantly weakened on 2025-10-31.72. The absorption line of NaI D is clearly seen in both epochs, suggesting that this object suffers from extinction. The evolution is similar to that of the luminous red nova AT 2019zhd, reported by Pastorello et al. (2021). From this similarity and the luminosity of the optical event, we propose that this event is likely a luminous red nova in M31, consistent with the common-envelope transient scenario of WNTR23bzdiq proposed by Karambelkar et al. (2025).
The following Classification spectrum was provided:
Obsdate: 2025-10-29 14:38:24
Instrument: Other
Telescope: Other
Remarks: See ATel #17468. A spectroscopic follow-up observation with KOOLS-IFU mounted on the 3.8-m Seimei telescope at Okayama Observatory of Kyoto University. The spectral resolution is ~ 500, and the wavelength coverage is 4100-8500 A.
Details of the object and its spectra can be viewed here: https://www.wis-tns.org/object/2025abao