SN 2021foa, a transitional event between a Type IIn (SN 2009ip-like) and a Type Ibn supernova
Year: 2022
Type: article
Abstract: We present photometric and spectroscopic data of the unusual interacting supernova (SN) 2021foa. It rose to an absolute magnitude peak ofMr = −18 mag in 20 days. The initial light curve decline shows some luminosity fluctuations before a long-lasting flattening. A faint source (Mr ∼ −14 mag) was detected in the weeks preceding the main event, showing a slowly rising luminosity trend. Ther-band absolute light curve is very similar to those of SN 2009ip-like events, with a faint and shorter duration brightening (‘Event A’) followed by a much brighter peak (‘Event B’). The early spectra of SN 2021foa show a blue continuum with narrow (∼400 km s−1) H emission lines that, two weeks later, reveal a complex profile, with a narrow P Cygni on top of an intermediate-width (∼2700 km s−1) component. At +12 days, metal lines in emission appear and He Ilines become very strong, with He Iλ5876 reaching half of the Hαluminosity, much higher than in previous SN 2009ip-like objects. We propose that SN 2021foa is a transitional event between the H-rich SN 2009ip-like SNe and the He-rich Type Ibn SNe.
Source: Astronomy and Astrophysics
Institutions: Universidad Andrés Bello, Millennium Institute of Astrophysics, Osservatorio Astronomico di Padova, National Institute for Astrophysics, University College Dublin, Aarhus University, Tsinghua University, Institute of Space Sciences, Brera Astronomical Observatory, University of Turku, Stockholm University, AlbaNova, Max Planck Institute for Astrophysics, Liverpool John Moores University, University of Padua
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,580
Funders: Aarhus Universitet, Villum Fonden, Royal Society, Science Foundation Ireland, Academy of Finland, China Postdoctoral Science Foundation, Ministero dell’Istruzione, dell’Università e della Ricerca, Liverpool John Moores University, Ministerio de Ciencia e Innovación, Universitetet i Oslo, Háskóli Íslands, Turun Yliopisto, Stockholms Universitet, Agencia Nacional de Investigación y Desarrollo, Science and Technology Facilities Council
Awards: G1122307025, The new frontier of Multi-Messenger Astrophysics: follow-up of electromagnetic transient counterparts of gravitational wave sources., G15967578, G2635449810, G3439265645, G3690828678, G4314687588, The dynamic sky: environments of supernovae and astrophysical transients, G4570936650, G4635723693, G4655338613, G4741463335, G5506409483, G5728085972, G57481727, G59132117, G7424809977, G7773936698, G8211594416, G993116129
OpenAlex ID: W4282019407