JWST Discovery of Dust Reservoirs in Nearby Type IIP Supernovae 2004et and 2017eaw

TL;DR

This study uses JWST observations to detect and analyze dust in two nearby supernovae, providing new insights into dust formation and its potential role in cosmic dust budgets.

Contribution

First JWST mid-infrared observations of supernovae at late times, constraining dust masses, geometry, and heating mechanisms, advancing understanding of supernovae as dust sources.

Findings

Dust masses >0.014 and >4e-4 solar masses for the two supernovae.

Dust is heated by shock interaction with circumstellar medium.

SN 2004et has the second highest inferred dust mass among extragalactic SNe.

Abstract

Supernova (SN) explosions have been sought for decades as a possible source of dust in the Universe, providing the seeds of galaxies, stars, and planetary systems. SN 1987A offers one of the most promising examples of significant SN dust formation, but until the James Webb Space Telescope (JWST), instruments have traditionally lacked the sensitivity at both late times (>1 yr post-explosion) and longer wavelengths (i.e., >10 um) to detect analogous dust reservoirs. Here we present JWST/MIRI observations of two historic Type IIP SNe, 2004et and SN 2017eaw, at nearly 18 and 5 yr post-explosion, respectively. We fit the spectral energy distributions as functions of dust mass and temperature, from which we are able to constrain the dust geometry, origin, and heating mechanism. We place a 90% confidence lower limit on the dust masses for SNe 2004et and 2017eaw of >0.014 and >4e-4 M_sun, respectively. More dust may exist at even colder temperatures or may be obscured by high optical depths. We conclude dust formation in the ejecta to be the most plausible and consistent scenario. The observed dust is radiatively heated to ~100-150 K by ongoing shock interaction with the circumstellar medium. Regardless of the best fit or heating mechanism adopted, the inferred dust mass for SN 2004et is the second highest (next to SN 1987A) inferred dust mass in extragalactic SNe thus far, promoting the prospect of SNe as potential significant sources of dust in the Universe.