A Diversity of Wave-driven Pre-supernova Outbursts

TL;DR

This study investigates wave-driven energy transport in massive star progenitors, revealing how it can cause pre-supernova outbursts and varies with stellar mass and burning stages, using advanced stellar evolution models.

Contribution

It introduces a more realistic wave spectrum and damping effects in stellar models, refining estimates of wave energy transfer prior to supernovae.

Findings

Low-mass progenitors can have significant outbursts during neon ignition.

High-mass progenitors transmit more energy closer to collapse.

Wave energy transfer varies with stellar mass and burning stage.

Abstract

Many core-collapse supernova progenitors show indications of enhanced pre-supernova (SN) mass loss and outbursts, some of which could be powered by wave energy transport within the progenitor star. Depending on the star's structure, convectively excited waves driven by late stage nuclear burning can carry substantial energy from the core to the envelope, where the wave energy is dissipated as heat. We examine the process of wave energy transport in single-star SNe progenitors with masses between $11-50 M_{\odot}$. Using MESA stellar evolution simulations, we evolve stars until core collapse and calculate the wave power produced and transmitted to the stars' envelopes. These models improve upon prior efforts by incorporating a more realistic wave spectrum and non-linear damping effects, reducing our wave heating estimates by $\sim$ 1 order of magnitude compared to prior work. We find that waves excited during oxygen/neon burning typically transmit $10^{46-47}$ erg of energy at 0.1-10 years before core collapse in typical ($M < 30 M_\odot$) SN progenitors. High-mass progenitors can often transmit $\sim 10^{47-48}$ erg of energy during oxygen/neon burning, but this tends to occur later, at about 0.01-0.1 years before core collapse. Pre-SN outbursts may be most pronounced in low-mass SN progenitors ($M \lesssim 12 M_\odot$) undergoing semi-degenerate neon ignition, and in high-mass progenitors ($M \gtrsim 30 M_\odot$) exhibiting convective shell mergers.