A WC/WO star exploding within an expanding carbon-oxygen-neon nebula
Abstract
The final explosive fate of massive stars, and the nature of the compact remnants they leave behind (black holes and neutron stars), are major open questions in astrophysics. Many massive stars are stripped of their outer hydrogen envelopes as they evolve. Such Wolf-Rayet (W-R) stars emit strong and rapidly expanding (v_wind>1000 km/s) winds indicating a high escape velocity from the stellar surface. A fraction of this population is also helium depleted, with spectra dominated by highly-ionized emission lines of carbon and oxygen (Types WC/WO). Evidence indicates that the most commonly-observed supernova (SN) explosions that lack hydrogen and helium (Types Ib/Ic) cannot result from massive WC/WO stars, leading some to suggest that most such stars collapse directly into black holes without a visible supernova explosions. Here, we present observations of supernova SN 2019hgp, discovered about a day after explosion. The short rise time and rapid decline place it among an emerging population of rapidly-evolving transients (RETs). Spectroscopy reveals a rich set of emission lines indicating that the explosion occurred within a nebula composed of carbon, oxygen, and neon. Narrow absorption features show that this material is expanding at relatively high velocities (>1500 km/s) requiring a compact progenitor. Our observations are consistent with an explosion of a massive WC/WO star, and suggest that massive W-R stars may be the progenitors of some rapidly evolving transients.
Keywords
Cite
@article{arxiv.2111.12435,
title = {A WC/WO star exploding within an expanding carbon-oxygen-neon nebula},
author = {A. Gal-Yam and R. Bruch and S. Schulze and Y. Yang and D. A. Perley and I. Irani and J. Sollerman and E. C. Kool and M. T. Soumagnac and O. Yaron and N. L. Strotjohann and E. Zimmerman and C. Barbarino and S. R. Kulkarni and M. M. Kasliwal and K. De and Y. Yao and C. Fremling and L. Yan and E. O. Ofek and C. Fransson and A. V. Filippenko and W. Zheng and T. G. Brink and C. M. Copperwheat and R. J. Foley and J. Brown and M. Siebert and G. Leloudas and A. L. Cabrera-Lavers and D. Garcia-Alvarez and A. Marante-Barreto and S. Frederick and T. Hung and J. C. Wheeler and J. Vinko and B. P. Thomas and M. J. Graham and D. A. Duev and A. J. Drake and R. Dekany and E. C. Bellm and B. Rusholme and D. L. Shupe and I. Andreoni and Y. Sharma and R. Riddle and J. van Roestel and N. Knezevic},
journal= {arXiv preprint arXiv:2111.12435},
year = {2022}
}
Comments
Unedited author version, Nature in press