Carbon Monoxide in the Cold Debris of Supernova 1987A

TL;DR

This study reports the first detection of cold CO and SiO molecules in the ejecta of supernova 1987A using submillimeter observations, revealing the physical conditions and chemical composition of the remnant.

Contribution

It provides the first spectroscopic detection of cold molecular gas in a supernova remnant and demonstrates the effectiveness of submillimeter observations for studying supernova ejecta.

Findings

Detection of cold CO and SiO molecules in SN1987A ejecta.

At least 0.01 solar masses of CO at >14 K are present.

Molecular emission confined within 35% of a spherical volume expanding at ~2000 km/s.

Abstract

We report spectroscopic and imaging observations of rotational transitions of cold CO and SiO in the ejecta of SN1987A, the first such emission detected in a supernova remnant. In addition to line luminosities for the CO J=1-0, 2-1, 6-5, and 7-6 transitions, we present upper limits for all other transitions up to J=13-12, collectively measured from the Atacama Large Millimeter Array (ALMA), the Atacama Pathfinder EXperiment (APEX), and the Herschel Spectral and Photometric Imaging REceiver (SPIRE). Simple models show the lines are emitted from at least 0.01 solar masses of CO at a temperature > 14 K, confined within at most 35% of a spherical volume expanding at ~ 2000 km/s. Moreover, we locate the emission within 1'' of the central debris. These observations, along with a partial observation of SiO, confirm the presence of cold molecular gas within supernova remnants and provide insight into the physical conditions and chemical processes in the ejecta. Furthermore, we demonstrate the powerful new window into supernova ejecta offered by submillimeter observations.