SN2019dge: A Helium-rich Ultra-stripped Envelope Supernova

Yuhan Yao*, Kishalay De, Mansi M. Kasliwal, Anna Y.Q. Ho, Steve Schulze, Zhihui Li, S. R. Kulkarni, Andrew Fruchter, David Rubin, Daniel A. Perley, Jim Fuller, Anthony L. Piro, C. Fremling, Eric C. Bellm, Rick Burruss, Dmitry A. Duev, Michael Feeney, Avishay Gal-Yam, V. Zach Golkhou, Matthew J. GrahamGeorge Helou, Thomas Kupfer, Russ R. Laher, Frank J. Masci, Adam A. Miller, Ben Rusholme, David L. Shupe, Roger Smith, Jesper Sollerman, Maayane T. Soumagnac, Jeffry Zolkower

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

We present observations of ZTF18abfcmjw (SN2019dge), a helium-rich supernova with a fast-evolving light curve indicating an extremely low ejecta mass (≈0.33 M o˙) and low kinetic energy (≈1.3 1050 erg). Early-time (<4 days after explosion) photometry reveals evidence of shock cooling from an extended helium-rich envelope of ∼0.1 M o˙ located ∼1.2 1013 cm from the progenitor. Early-time He II line emission and subsequent spectra show signatures of interaction with helium-rich circumstellar material, which extends from ⪆5 1013 cm to ⪆2 1016 cm. We interpret SN2019dge as a helium-rich supernova from an ultra-stripped progenitor, which originates from a close binary system consisting of a mass-losing helium star and a low-mass main-sequence star or a compact object (i.e., a white dwarf, a neutron star, or a black hole). We infer that the local volumetric birth rate of 19dge-like ultra-stripped SNe is in the range of 1400-8200 (i.e., 2%-12% of core-collapse supernova rate). This can be compared to the observed coalescence rate of compact neutron star binaries that are not formed by dynamical capture.

Original languageEnglish (US)
Article number46
JournalAstrophysical Journal
Volume900
Issue number1
DOIs
StatePublished - Sep 1 2020

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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