JWST Imaging of the Cartwheel Galaxy Reveals Dust Associated with SN 2021afdx

TL;DR

This study uses JWST infrared imaging to analyze supernova SN 2021afdx in the Cartwheel Galaxy, revealing dust properties and indicating an infrared echo from preexisting dust, demonstrating JWST's potential in supernova dust studies.

Contribution

First infrared analysis of a Type IIb supernova with JWST, showing dust mass and echo effects, expanding understanding of dust in supernova environments.

Findings

Derived dust mass of approximately 3.8 x 10^-3 solar masses.

Detected infrared echo from preexisting dust, not newly formed dust.

Demonstrated JWST's capability to study supernova dust in detail.

Abstract

We present near- and mid-infrared (0.9-18 $\mu$m) photometry of supernova (SN) 2021afdx, which was imaged serendipitously with the James Webb Space Telescope (JWST) as part of its Early Release Observations of the Cartwheel Galaxy. Our ground-based optical observations show it is likely to be a Type IIb SN, the explosion of a yellow supergiant, and its infrared spectral energy distribution (SED) $\approx$200 days after explosion shows two distinct components, which we attribute to hot ejecta and warm dust. By fitting models of dust emission to the SED, we derive a dust mass of $(3.8_{-0.3}^{+0.5}) \times 10^{-3}\ M_\odot$, which is the highest yet observed in a Type IIb SN but consistent with other Type II SNe observed by the Spitzer Space Telescope. We also find that the radius of the dust is significantly larger than the radius of the ejecta, as derived from spectroscopic velocities during the photospheric phase, which implies that we are seeing an infrared echo off of preexisting dust in the progenitor environment, rather than dust newly formed by the SN. Our results show the power of JWST to address questions of dust formation in SNe, and therefore the presence of dust in the early universe, with much larger samples than have been previously possible.