AstroNote 2020-100

AT2020jfo is a young, rising supernova in the nearby spiral galaxy M61 (Schulze et al., AstroNote 2020-99).  During the 24 hours following its discovery we obtained three optical spectra using the Nordic Optical Telescope (ALFOSC) and Liverpool Telescope (SPRAT) on La Palma and with the 60-inch Telescope (SEDM) at Palomar Observatory.  The ALFOSC spectrum was taken using grism 4. 

All three spectra are dominated by a blue and very hot continuum with weak features.  The most prominent of these is a broad P-cygni like feature centered at approximately 4500 Angstroms, likely blueshifted helium.  The spectra also consistently show a weaker but significant broad feature at 6500 Angstroms, likely H-alpha.

Anaysis of the spectra using SNID (Blondin & Tonry 2007, 2007ApJ...666.1024B) shows a good match to SN 1999gi, a Type IIP SN, about 7 days before maximum light.  We suggest that SN 2020jfo is a young Type II supernova.

We thank Teet Kuutma and the NOT staff for obtaining these service observations.