Spectroscopic confirmation and photometry of the nova candidate AT2021ypn

ATel #14919; A. Vinokurov, S. Fabrika, A. Sarkisyan, Yu. Solovyeva, A. Grokhovskaya (SAO RAS), A. Valcheva, P. Nedialkov (Sofia University, Bulgaria)
on 14 Sep 2021; 20:57 UT
Credential Certification: Antoniya Valcheva (valcheva@phys.uni-sofia.bg)

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We report the optical spectroscopic confirmation of the recent M31 nova candidate AT2021ypn (= PSP21H) discovered on 2021/09/11.602 UT by Xingming Observatory Sky Survey (XOSS). The spectrum was obtained on 2021-14-01.625 UT using the Russian 6m telescope (BTA) equipped with the SCORPIO-2 spectrograph, with spectral resolution of 4.5 Å in the 3650-7250 Å range.

Direct imaging of the region in filters V, Rc were carried out immediately before spectroscopy. The measured magnitudes (V = 17.19 ± 0.05, Rc = 16.99 ± 0.06) indicate a decrease in the brightness of the object by about 0.6 mag in R band compared to the value obtained two days earlier (ATel #14913).

The spectrum reveals the broad Balmer emission lines together with numerous strong Fe II lines with FWHMs in range of 1900-2700 km/s (the spectrum can be found here). The hydrogen H-alpha has single peak profile with narrow absorption component on the blue wing, while H-beta line has clear two components structure. Other hydrogen lines are blended by Fe II line or are noisy. Some of the iron lines are likely to have a flat top, others (for example Fe II 5018 Å) demonstrate a two-peak profile. We conclude that this M31 nova belongs to the Fe II class.

The work was performed as part of the government contract of the SAO RAS approved by the Ministry of Science and Higher Education of the Russian Federation. The work was also performed as part of the NSF Bulgaria grant DN18/10-11.12.2017.