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Research output: Contribution to Journal/Magazine › Journal article
Research output: Contribution to Journal/Magazine › Journal article
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TY - JOUR
T1 - A Carbon/Oxygen-dominated Atmosphere Days after Explosion for the “Super-Chandrasekhar” Type Ia SN 2020esm
AU - Dimitriadis, Georgios
AU - Foley, Ryan J.
AU - Arendse, Nikki
AU - Coulter, David A.
AU - Jacobson-Galán, Wynn V.
AU - Siebert, Matthew R.
AU - Izzo, Luca
AU - Jones, David O.
AU - Kilpatrick, Charles D.
AU - Pan, Yen-Chen
AU - Taggart, Kirsty
AU - Auchettl, Katie
AU - Gall, Christa
AU - Hjorth, Jens
AU - Kasen, Daniel
AU - Piro, Anthony L.
AU - Raimundo, Sandra I.
AU - Ramirez-Ruiz, Enrico
AU - Rest, Armin
AU - Swift, Jonathan J.
AU - Woosley, Stan E.
PY - 2022/3/1
Y1 - 2022/3/1
N2 - Seeing pristine material from the donor star in a type Ia supernova (SN Ia) explosion can reveal the nature of the binary system. In this paper, we present photometric and spectroscopic observations of SN 2020esm, one of the best-studied SNe of the class of "super-Chandrasekhar"SNe Ia (SC SNe Ia), with data obtained -12 to +360 days relative to peak brightness, obtained from a variety of ground- and space-based telescopes. Initially misclassified as a type II supernova, SN 2020esm peaked at M B = -19.9 mag, declined slowly ( "m 15(B) = 0.92 mag), and had particularly blue UV and optical colors at early times. Photometrically and spectroscopically, SN 2020esm evolved similarly to other SC SNe Ia, showing the usual low ejecta velocities, weak intermediate-mass elements, and the enhanced fading at late times, but its early spectra are unique. Our first few spectra (corresponding to a phase of ≳10 days before peak) reveal a nearly pure carbon/oxygen atmosphere during the first days after explosion. This composition can only be produced by pristine material, relatively unaffected by nuclear burning. The lack of H and He may further indicate that SN 2020esm is the outcome of the merger of two carbon/oxygen white dwarfs. Modeling its bolometric light curve, we find an 56Ni mass of 1.23-0.14+0.14 M o˙ and an ejecta mass of 1.75-0.20+0.32 M o˙, in excess of the Chandrasekhar mass. Finally, we discuss possible progenitor systems and explosion mechanisms of SN 2020esm and, in general, the SC SNe Ia class.
AB - Seeing pristine material from the donor star in a type Ia supernova (SN Ia) explosion can reveal the nature of the binary system. In this paper, we present photometric and spectroscopic observations of SN 2020esm, one of the best-studied SNe of the class of "super-Chandrasekhar"SNe Ia (SC SNe Ia), with data obtained -12 to +360 days relative to peak brightness, obtained from a variety of ground- and space-based telescopes. Initially misclassified as a type II supernova, SN 2020esm peaked at M B = -19.9 mag, declined slowly ( "m 15(B) = 0.92 mag), and had particularly blue UV and optical colors at early times. Photometrically and spectroscopically, SN 2020esm evolved similarly to other SC SNe Ia, showing the usual low ejecta velocities, weak intermediate-mass elements, and the enhanced fading at late times, but its early spectra are unique. Our first few spectra (corresponding to a phase of ≳10 days before peak) reveal a nearly pure carbon/oxygen atmosphere during the first days after explosion. This composition can only be produced by pristine material, relatively unaffected by nuclear burning. The lack of H and He may further indicate that SN 2020esm is the outcome of the merger of two carbon/oxygen white dwarfs. Modeling its bolometric light curve, we find an 56Ni mass of 1.23-0.14+0.14 M o˙ and an ejecta mass of 1.75-0.20+0.32 M o˙, in excess of the Chandrasekhar mass. Finally, we discuss possible progenitor systems and explosion mechanisms of SN 2020esm and, in general, the SC SNe Ia class.
U2 - 10.3847/1538-4357/ac4780
DO - 10.3847/1538-4357/ac4780
M3 - Journal article
VL - 927
JO - The Astrophysical Journal
JF - The Astrophysical Journal
SN - 0004-637X
IS - 1
M1 - 78
ER -