Spectroscopic confirmation of the 2025 eruption of the Recurrent Nova M31N 2008-12a
ATel #17520; Shatakshi Chamoli (IIA Bengaluru), Judhajeet Basu (IIA Bengaluru), G. C. Anupama (IIA Bengaluru), Sudhanshu Barway (IIA Bengaluru), Surya (IIA Bengaluru)
on 2 Dec 2025; 15:13 UT
Credential Certification: Judhajeet Basu (judhajeet.basu@iiap.res.in)
Subjects: Optical, Cataclysmic Variable, Nova
We report the spectroscopic observation of the 18th consecutive eruption of M31N 2008-12a, the recurrent nova with the shortest recurrence period of approximately 1 year (Darnley et al 2016, Henze et al 2018, Basu et al 2024). The 2025 eruption of the object was discovered on Nov. 30.36 (K. Itagaki et al. ATel #17511) and also reported in images taken 6 hours prior to discovery (F. Diaz-Segado et al. ATel #17514).
A spectrum of the fast-fading object was taken on 2025 Dec 01.79 using Gr7 of the HFOSC instrument mounted on the 2m HCT located at IAO, Hanle, India, with an exposure time of 3600 s. The spectrum shows a blue continuum, clearly featuring H-alpha and H-beta emission, along with the He I emission near 5876 A. The FWHM, estimated by fitting a single Gaussian, are roughly 2400 km/s for H-alpha and 1830 km/s for H-beta. The spectrum is similar to that reported for its previous outbursts, observed within 3 days of eruption. This confirms the recurrence of M31N 2008-12a and its 2025 eruption.
We continue to monitor the object with facilities at IAO. More observations are encouraged.
We thank the HCT observers for sparing time to carry out the ToO observations. IAO is operated by the Indian Institute of Astrophysics, Bengaluru, India.
