Light Curves of the Neutron Star Merger GW170817/SSS17a: Implications for R-Process Nucleosynthesis

TL;DR

This paper presents detailed multi-wavelength light curves of the neutron star merger GW170817's optical counterpart, providing evidence that such mergers significantly contribute to the universe's heavy element formation through r-process nucleosynthesis.

Contribution

It offers the first comprehensive multi-band light curves of SSS17a, revealing multiple ejecta components and quantifying heavy element production from neutron star mergers.

Findings

Light curves show multiple ejecta components with different lanthanide abundances.

At least ~0.05 solar masses of heavy elements were produced.

Neutron star mergers significantly contribute to r-process nucleosynthesis.

Abstract

On 2017 August 17, gravitational waves were detected from a binary neutron star merger, GW170817, along with a coincident short gamma-ray burst, GRB170817A. An optical transient source, Swope Supernova Survey 17a (SSS17a), was subsequently identified as the counterpart of this event. We present ultraviolet, optical and infrared light curves of SSS17a extending from 10.9 hours to 18 days post-merger. We constrain the radioactively-powered transient resulting from the ejection of neutron-rich material. The fast rise of the light curves, subsequent decay, and rapid color evolution are consistent with multiple ejecta components of differing lanthanide abundance. The late-time light curve indicates that SSS17a produced at least ~0.05 solar masses of heavy elements, demonstrating that neutron star mergers play a role in r-process nucleosynthesis in the Universe.