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Updated: Oct 6, 2025
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How to Ignite an Atmospheric Pressure Microwave Plasma Torch without Any Additional Igniters
Published on: April 16, 2015
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A WC/WO star exploding within an expanding carbon-oxygen-neon nebula.
A Gal-Yam1, R Bruch2, S Schulze2,3
1Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot, Israel. avishay.gal-yam@weizmann.ac.il.
Nature
|January 13, 2022
Summary
Massive Wolf-Rayet stars, particularly helium-depleted WC/WO types, may be progenitors of rapidly evolving transients. Observations of SN 2019hgp suggest these stars can explode, challenging previous theories of direct black hole collapse.
Area of Science:
- Astrophysics
- Stellar Evolution
- Transient Astronomy
Background:
- The final fate of massive stars and their compact remnants (black holes, neutron stars) remain open questions.
- Massive stars losing hydrogen envelopes evolve into Wolf-Rayet stars with powerful winds.
- Helium-depleted WC/WO Wolf-Rayet stars are suspected to collapse directly into black holes, avoiding visible supernovae.
Purpose of the Study:
- To investigate the progenitor of the rapidly evolving transient SN 2019hgp.
- To determine if massive Wolf-Rayet stars can produce observable supernova explosions.
- To understand the connection between Wolf-Rayet stars and hydrogen/helium-poor supernova types.
Main Methods:
- Observational astronomy utilizing spectroscopy of SN 2019hgp shortly after its explosion.
- Analysis of emission and absorption line features to determine the composition and expansion velocity of the ejecta.
- Comparison of observed transient properties with theoretical models of stellar evolution and supernovae.
Main Results:
- SN 2019hgp exhibited a short rise time and rapid decline, characteristic of rapidly evolving transients.
- Spectroscopy revealed emission lines from carbon, oxygen, and neon, and high-velocity absorption features (>1,500 km/s).
- These findings are consistent with an explosion originating from a massive WC/WO star.
Conclusions:
- Massive Wolf-Rayet stars, specifically WC/WO types, can be progenitors of observable supernova explosions.
- The observed properties of SN 2019hgp support the hypothesis that these stars can lead to rapidly evolving transients.
- This challenges the notion that most such stars undergo direct black hole collapse without a visible explosion.
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