Recombination Effects on Supernova Light Curves

Abstract

The light curves of type-II supernovae (SNe) are believed to be highly affected by recombination of hydrogen that takes place in their envelopes. In this work, we analytically investigate the transition from a fully ionized envelope to a partially recombined one and its effects on the SN light curve. The motivation is to establish the underlying processes that dominate the evolution at late times when recombination takes place in the envelope, yet early enough so that ${}^{56}$Ni decay is a negligible source of energy. We consider the diffusion of photons through the envelope while analyzing the ionization fraction and the coupling between radiation and gas, and find that the main effect of recombination is on the evolution of the observed temperature. Before recombination the temperature decreases relatively fast, while after recombination starts it significantly reduces the rate at which the observed temperature drops with time. This behaviour is the main cause for the observed flattening in the optical bands, where for a typical red supergiant explosion, the recombination wave affects the bolometric luminosity only mildly during most of the photospheric phase. Moreover, the plateau phase observed in some type-II SNe is not a generic result of recombination, and it also depends on the density structure of the progenitor. This is one possible explanation to the different light curve decay rates observed in type II (P and L) SNe.

Submitted to ApJ, after first referee report. This is a major revision of arXiv:1404.6313

References in corpus (18)

• Nearby Supernova Rates from the Lick Observatory Supernova Search. II. The Observed Luminosity Functions and Fractions of Supernovae in a Complete Sample
• The Expulsion of Stellar Envelopes in Core-Collapse Supernovae
• Early supernovae light-curves following the shock-breakout
• Characterizing the V-band light-curves of hydrogen-rich type II supernovae
• The diversity of Type II supernova versus the similarity in their progenitors
• Type II Supernovae: Model Light Curves and Standard Candle Relationships
• Photometry and Spectroscopy of the Type IIP SN 1999em from Outburst to Dust Formation
• The early UV/Optical emission from core-collapse supernovae
• Type II-Plateau supernova radiation: dependencies on progenitor and explosion properties
• Hydrodynamical models of Type II-Plateau Supernovae
• Caltech Core-Collapse Project (CCCP) Observations of Type II Supernovae: Evidence for Three Distinct Photometric Subtypes
• An optimal hydrodynamic model for the normal Type IIP supernova 1999em
• Bolometric Corrections for optical light curves of Core-collapse Supernovae
• Supernova 2012aw - a high-energy clone of archetypal type IIP SN 1999em
• Bolometric Light Curves for 33 Type II-Plateau Supernovae
• An Emerging Coherent Picture of Red Supergiant Supernova Explosions
• The Evolution of Temperature and Bolometric Luminosity in Type-II Supernovae
• Bolometric Lightcurves of Peculiar Type II-P Supernovae

Cited by in corpus (9)

• Light Curve Model for Luminous Red Novae and Inferences about the Ejecta of Stellar Mergers
• Shock breakouts from red supergiants: analytical and numerical predictions
• Analytic Light Curves of Dense CSM Shock Breakout and Cooling
• A Massive Star's Dying Breaths: Pulsating Red Supergiants and Their Resulting Type IIP Supernovae
• Limits on mass outflow from optical tidal disruption events
• A systematic study on the rise time-peak luminosity relation for bright optical transients powered by wind shock breakout
• Precursors of Supernovae from Mass Eruption: Prospects for Early Warning of Nearby Core-collapse Supernovae
• Extremely energetic supernova explosions embedded in a massive circumstellar medium: the case of SN 2016aps
• Weak Mass Loss from the Red Supergiant Progenitor of the Type II SN 2021yja