Photometric and spectroscopic analysis of the Type II SN 2020jfo with a short plateau

B. Ailawadhi, R. Dastidar, K. Misra, R. Roy, D. Hiramatsu, D. A. Howell, T. G. Brink, W. Zheng, L. Galbany, M. Shahbandeh, I. Arcavi, C. Ashall, K. A. Bostroem, J. Burke, T. Chapman, Dimple, A. V. Filippenko, A. Gangopadhyay, A. Ghosh, A. M. Hoffman, G. Hosseinzadeh, C. Jennings, V. K. Jha, A. Kumar, E. Karamehmetoglu, C. McCully, E. McGinness, T. E. Müller-Bravo, Y. S. Murakami, S. B. Pandey, C. Pellegrino, L. Piscarreta, J. Rho, M. Stritzinger, J. Sunseri, S. D. Van Dyk, L. Yadav

Submitted on 5 November 2022


We present high-cadence photometric and spectroscopic observations of SN~2020jfo in ultraviolet and optical/near-infrared bands starting from 3 to 434 days after the explosion, including the earliest data with the 10.4\,m GTC. SN~2020jfo is a hydrogen-rich Type II SN with a relatively short plateau duration (67.0±0.6 days). When compared to other Type II supernovae (SNe) of similar or shorter plateau lengths, SN~2020jfo exhibits a fainter peak absolute V-band magnitude (MV=16.90±0.34 mag). SN~2020jfo shows significant Hα absorption in the plateau phase similar to that of typical SNe~II. The emission line of stable [Ni~II] λ7378, mostly seen in low-luminosity SNe~II, is very prominent in the nebular-phase spectra of SN~2020jfo. Using the relative strengths of [Ni~II] λ7378 and [Fe~II] λ7155, we derive the Ni/Fe production (abundance) ratio of 0.08--0.10, which is 1.5 times the solar value. The progenitor mass of SN~2020jfo from nebular-phase spectral modelling and semi-analytical modelling falls in the range of 12--15\,M. Furthermore, semi-analytical modelling suggests a massive H envelope in the progenitor of SN~2020jfo, which is unlikely for SNe~II having short plateaus.


Comment: 20 pages (plus 5 pages appendix), 19 figures, Accepted for publication in MNRAS

Subjects: Astrophysics - High Energy Astrophysical Phenomena; Astrophysics - Solar and Stellar Astrophysics


The narrow Na~I~D absorption dip due to the host galaxy, M61, in the two highest-SNR spectra (21.2 and 25.2 d) and the composite spectrum of SN~2020jfo.