# A solar-type star polluted by calcium-rich supernova ejecta inside the supernova remnant RCW 86

## TL;DR

This paper reports the discovery of a solar-type star polluted by calcium-rich supernova ejecta inside the supernova remnant RCW 86, providing evidence that calcium-rich supernovae can originate from core-collapse explosions.

## Contribution

It presents the first observational evidence linking calcium-rich supernovae to core-collapse origins through pollution in a binary system within a supernova remnant.

## Key findings

- Solar-type star strongly polluted with calcium and other elements.
- Supernova progenitor was a moving star that lost mass before explosion.
- Calcium-rich supernovae can arise from core-collapse explosions.

## Abstract

When a massive star in a binary system explodes as a supernova its companion star may be polluted with heavy elements from the supernova ejecta. Such a pollution had been detected in a handful of post-supernova binaries (Gonzalez Hernandez et al. 2011), but none of them is associated with a supernova remnant. We report the discovery of a solar-type star in a close, eccentric binary system with a neutron star within the young Galactic supernova remnant RCW 86. Our discovery implies that the supernova progenitor was a moving star, which exploded near the edge of its wind bubble and lost most of its initial mass due to common-envelope evolution shortly before core collapse. We find that the solar-type star is strongly polluted with calcium and other elements, which places the explosion within the class of calcium-rich supernovae -- faint and fast transients (Filippenko et al. 2003; Kasliwal et al. 2012}, whose origin is strongly debated (Kawabata et al. 2010; Waldman et al. 2011), and provides the first observational evidence that supernovae of this type can arise from core-collapse explosions (Kawabata et al. 2010; Moriya et al. 2010).