Supernova Ejecta with Crystalline Silicate Dust in the Supernova Remnant MSH 15-52

TL;DR

This study investigates the crystalline silicate dust in the supernova remnant MSH 15-52, revealing that the central source IRS1 likely originates from supernova ejecta and may contain newly-formed crystalline silicate dust.

Contribution

First high-resolution MIR imaging and spectral analysis of IRS1, demonstrating its origin from SN ejecta and suggesting in-situ formation of crystalline silicate dust.

Findings

IRS1 shows inhomogeneous morphology with clumps and diffuse emission.

Spectral modeling indicates IRS1's composition resembles SN ejecta with enhanced metals.

IRS1 likely contains newly-formed crystalline silicate dust in SN ejecta.

Abstract

IRAS 15099-5856 in the young supernova remnant (SNR) MSH 15-52 is the first and only SNR-associated object with crystalline silicate dust detected so far, although its nature and the origin of the crystalline silicate are still unclear. In this paper, we present high-resolution mid-infrared (MIR) imaging observations of the bright central compact source IRS1 of IRAS 15099-5856 to study the spatial distributions of gas and dust and the analysis of its Spitzer MIR spectrum to explore the origin of IRS1. The MIR images obtained with the T-ReCS attached on the Gemini South telescope show a complicated, inhomogeneous morphology of IRS1 with bright clumps and diffuse emission in [Ne II] 12.81 $\mu$m and Qa 18.30 $\mu$m, which confirms that IRS1 is an extended source externally heated by the nearby O star Muzzio 10, a candidate for the binary companion of the progenitor star. The Spitzer MIR spectrum reveals several ionic emission lines including a strong [Ne II] 12.81 $\mu$m line, but no hydrogen line is detected. We model the spectrum using the photoionization code CLOUDY with varying elemental composition. The elemental abundance of IRS1 derived from the model is close to that of SN ejecta with depleted hydrogen and enhanced metals, particularly neon, argon, and iron. Our results imply that IRS1 originates from the SN ejecta and suggest the possibility of the formation of crystalline silicate in newly-formed SN dust.