The Astrophysical Journal (Jan 2023)
SN 2020jgb: A Peculiar Type Ia Supernova Triggered by a Helium-shell Detonation in a Star-forming Galaxy
- Chang Liu,
- Adam A. Miller,
- Abigail Polin,
- Anya E. Nugent,
- Kishalay De,
- Peter E. Nugent,
- Steve Schulze,
- Avishay Gal-Yam,
- Christoffer Fremling,
- Shreya Anand,
- Igor Andreoni,
- Peter Blanchard,
- Thomas G. Brink,
- Suhail Dhawan,
- Alexei V. Filippenko,
- Kate Maguire,
- Tassilo Schweyer,
- Huei Sears,
- Yashvi Sharma,
- Matthew J. Graham,
- Steven L. Groom,
- David Hale,
- Mansi M. Kasliwal,
- Frank J. Masci,
- Josiah Purdum,
- Benjamin Racine,
- Jesper Sollerman,
- Shrinivas R. Kulkarni
Affiliations
- Chang Liu
- ORCiD
- Department of Physics and Astronomy, Northwestern University , 2145 Sheridan Road, Evanston, IL 60208, USA ; [email protected]; Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University , 1800 Sherman Ave, Evanston, IL 60201, USA
- Adam A. Miller
- ORCiD
- Department of Physics and Astronomy, Northwestern University , 2145 Sheridan Road, Evanston, IL 60208, USA ; [email protected]; Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University , 1800 Sherman Ave, Evanston, IL 60201, USA
- Abigail Polin
- ORCiD
- The Observatories of the Carnegie Institution for Science , 813 Santa Barbara Street, Pasadena, CA 91101, USA; TAPIR, Walter Burke Institute for Theoretical Physics , 350-17, Caltech, Pasadena, CA 91125, USA
- Anya E. Nugent
- ORCiD
- Department of Physics and Astronomy, Northwestern University , 2145 Sheridan Road, Evanston, IL 60208, USA ; [email protected]; Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University , 1800 Sherman Ave, Evanston, IL 60201, USA
- Kishalay De
- ORCiD
- MIT-Kavli Institute for Astrophysics and Space Research , 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Peter E. Nugent
- ORCiD
- Department of Astronomy, University of California , Berkeley, CA 94720-3411, USA; Lawrence Berkeley National Laboratory , 1 Cyclotron Road, Berkeley, CA, 94720, USA
- Steve Schulze
- ORCiD
- The Oskar Klein Centre, Department of Physics, Stockholm University , Albanova University Center, SE-106 91 Stockholm, Sweden
- Avishay Gal-Yam
- ORCiD
- Department of Particle Physics and Astrophysics, Weizmann Institute of Science , 76100 Rehovot, Israel
- Christoffer Fremling
- ORCiD
- Caltech Optical Observatories, California Institute of Technology , Pasadena, CA 91125, USA; Division of Physics, Mathematics, and Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Shreya Anand
- ORCiD
- Cahill Center for Astrophysics, California Institute of Technology , Pasadena CA 91125, USA
- Igor Andreoni
- ORCiD
- Joint Space-Science Institute, University of Maryland , College Park, MD 20742, USA; Department of Astronomy, University of Maryland , College Park, MD 20742, USA; Astrophysics Science Division, NASA Goddard Space Flight Center , Mail Code 661, Greenbelt, MD 20771, USA
- Peter Blanchard
- ORCiD
- Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University , 1800 Sherman Ave, Evanston, IL 60201, USA
- Thomas G. Brink
- ORCiD
- Department of Astronomy, University of California , Berkeley, CA 94720-3411, USA
- Suhail Dhawan
- ORCiD
- Institute of Astronomy and Kavli Institute for Cosmology, University of Cambridge , Madingley Road, Cambridge CB3 0HA, UK
- Alexei V. Filippenko
- ORCiD
- Department of Astronomy, University of California , Berkeley, CA 94720-3411, USA
- Kate Maguire
- ORCiD
- School of Physics, Trinity College Dublin, The University of Dublin , Dublin 2, Ireland
- Tassilo Schweyer
- ORCiD
- The Oskar Klein Centre, Department of Astronomy, Stockholm University , AlbaNova, SE-106 91 Stockholm, Sweden
- Huei Sears
- ORCiD
- Department of Physics and Astronomy, Northwestern University , 2145 Sheridan Road, Evanston, IL 60208, USA ; [email protected]; Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University , 1800 Sherman Ave, Evanston, IL 60201, USA
- Yashvi Sharma
- ORCiD
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Matthew J. Graham
- ORCiD
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Steven L. Groom
- ORCiD
- IPAC, California Institute of Technology , 1200 E. California Boulevard, Pasadena, CA 91125, USA
- David Hale
- Caltech Optical Observatories, California Institute of Technology , Pasadena, CA 91125, USA
- Mansi M. Kasliwal
- ORCiD
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- Frank J. Masci
- ORCiD
- IPAC, California Institute of Technology , 1200 E. California Boulevard, Pasadena, CA 91125, USA
- Josiah Purdum
- ORCiD
- Caltech Optical Observatories, California Institute of Technology , Pasadena, CA 91125, USA
- Benjamin Racine
- ORCiD
- Aix Marseille Univ , CNRS/IN2P3, CPPM, Marseille, France
- Jesper Sollerman
- ORCiD
- The Oskar Klein Centre, Department of Astronomy, Stockholm University , AlbaNova, SE-106 91 Stockholm, Sweden
- Shrinivas R. Kulkarni
- ORCiD
- Division of Physics, Mathematics, and Astronomy, California Institute of Technology , Pasadena, CA 91125, USA
- DOI
- https://doi.org/10.3847/1538-4357/acbb5e
- Journal volume & issue
-
Vol. 946,
no. 2
p. 83
Abstract
The detonation of a thin (≲0.03 M _⊙ ) helium shell (He-shell) atop a ∼1 M _⊙ white dwarf (WD) is a promising mechanism to explain normal Type Ia supernovae (SNe Ia), while thicker He-shells and less massive WDs may explain some recently observed peculiar SNe Ia. We present observations of SN 2020jgb, a peculiar SN Ia discovered by the Zwicky Transient Facility (ZTF). Near maximum brightness, SN 2020jgb is slightly subluminous (ZTF g -band absolute magnitude −18.7 mag ≲ M _g ≲ −18.2 mag depending on the amount of host-galaxy extinction) and shows an unusually red color (0.2 mag ≲ g _ZTF − r _ZTF ≲ 0.4 mag) due to strong line-blanketing blueward of ∼5000 Å. These properties resemble those of SN 2018byg, a peculiar SN Ia consistent with an He-shell double detonation (DDet) SN. Using detailed radiative transfer models, we show that the optical spectroscopic and photometric evolution of SN 2020jgb is broadly consistent with a ∼0.95–1.00 M _⊙ (C/O core + He-shell) progenitor ignited by a ≳0.1 M _⊙ He-shell. However, one-dimensional radiative transfer models without non-local-thermodynamic-equilibrium treatment cannot accurately characterize the line-blanketing features, making the actual shell mass uncertain. We detect a prominent absorption feature at ∼1 μ m in the near-infrared (NIR) spectrum of SN 2020jgb, which might originate from unburnt helium in the outermost ejecta. While the sample size is limited, we find similar 1 μ m features in all the peculiar He-shell DDet candidates with NIR spectra obtained to date. SN 2020jgb is also the first peculiar He-shell DDet SN discovered in a star-forming dwarf galaxy, indisputably showing that He-shell DDet SNe occur in both star-forming and passive galaxies, consistent with the normal SN Ia population.
Keywords
