An outburst from a massive star 40 days before a supernova explosion

TL;DR

This paper reports the detection of a massive star's energetic outburst 40 days before a supernova, providing evidence for a causal link and supporting wave-driven pulsation models of pre-supernova mass loss.

Contribution

It presents the first direct observation of a pre-supernova outburst closely preceding a supernova explosion, confirming theoretical predictions about massive star evolution.

Findings

Detected a 40-day pre-supernova outburst with high energy and mass ejection.

The outburst's properties support wave-driven pulsation models.

The temporal link suggests a causal connection between outburst and supernova.

Abstract

Various lines of evidence suggest that very massive stars experience extreme mass-loss episodes shortly before they explode as a supernova. Interestingly, several models predict such pre-explosion outbursts. Establishing a causal connection between these mass-loss episodes and the final supernova explosion will provide a novel way to study pre-supernova massive-star evolution. Here we report on observations of a remarkable mass-loss event detected 40 days prior to the explosion of the Type IIn supernova SN 2010mc (PTF 10tel). Our photometric and spectroscopic data suggest that this event is a result of an energetic outburst, radiating at least 6x10^47 erg of energy, and releasing about 0.01 Solar mass at typical velocities of 2000 km/s. We show that the temporal proximity of the mass-loss outburst and the supernova explosion implies a causal connection between them. Moreover, we find that the outburst luminosity and velocity are consistent with the predictions of the wave-driven pulsation model and disfavor alternative suggestions.