Extended supernova shock breakout signals from inflated stellar envelopes

Abstract

Stars close to the Eddington luminosity can have large low-density inflated envelopes. We show that the rise times of shock breakout signals from supernovae can be extended significantly if supernova progenitors have an inflated stellar envelope. If the shock breakout occurs in such inflated envelopes, the shock breakout signals diffuse in them, and their rise time can be significantly extended. Then, the rise times of the shock breakout signals are dominated by the diffusion time in the inflated envelope rather than the light-crossing time of the progenitors. We show that our inflated Wolf-Rayet star models whose radii are of the order of the solar radius can have shock breakout signals which are longer than ~100 sec. The existence of inflated envelopes in Wolf-Rayet supernova progenitors may be related to the mysterious long shock breakout signal observed in Type Ib SN 2008D. Extended shock breakout signals may provide evidence for the existence of inflated stellar envelopes and can be used to constrain the physical properties of these enigmatic structures.

5 pages, 3 figures, 1 table, accepted by Astronomy & Astrophysics Letters, proofed in v2

References in corpus (9)

• Physical Properties of Wolf-Rayet Stars
• A Wolf-Rayet-like progenitor of supernova SN 2013cu from spectral observations of a wind
• From Shock Breakout to Peak and Beyond: Extensive Panchromatic Observations of the Type Ib Supernova 2008D associated with Swift X-ray Transient 080109
• The metamorphosis of Supernova SN2008D/XRF080109: a link between Supernovae and GRBs/Hypernovae
• The evolution of rotating very massive stars with LMC composition
• Progenitor Diagnostics for Stripped Core-Collapse Supernovae: Measured Metallicities at Explosion Sites
• Explosion and nucleosynthesis of low redshift pair instability supernovae
• SN 2008D: A Wolf-Rayet explosion through a thick wind
• The X-Ray Transient 080109 in NGC 2770: an X-Ray Flash Associated with a Normal Core-Collapse Supernova

Cited by in corpus (4)

• Signatures of a jet cocoon in early spectra of a supernova associated with a $\gamma$-ray burst
• The metallicity dependence of envelope inflation in massive stars
• The Wolf-Rayet Stellar Response To The Iron Opacity Bump: Envelope Inflation, Winds, and Microturbulence
• Hydrodynamical interaction of mildly relativistic ejecta with an ambient medium