Two Decades of Dust Evolution in SN 2005af through JWST, Spitzer, and Chemical Modeling

TL;DR

This paper addresses how dust evolves in core-collapse SNe by integrating two decades of infrared data (Spitzer and JWST) for SN 2005af with a chemical-kinetic dust-formation framework. The authors distinguish dust formed in the metal-rich SN ejecta from dust surviving in the pre-explosion wind, finding a predominantly carbon-rich ejecta dust mass of at least $0.02\,M_\odot$ and surviving CSM dust of about $(3$–$6)\times10^{-3}\,M_\odot$, for a total of at least $0.025\,M_\odot$. This approach provides a concrete, time-resolved template for dust production in SNe, linking early optical/IR signatures with late-time mid-IR detections and clarifying the relative roles of ejecta and CSM dust in the total dust budget of a SN. The results suggest efficient dust formation in the metal-rich core, with carbon-dominated ejecta dust and a smaller but non-negligible silicate component, offering valuable constraints for dust evolution in galaxies and the interpretation of IR observations of historic SNe. The study demonstrates the power of combining JWST with Spitzer-era data to resolve dust origin, composition, and mass in nearby SNe across decades, including a low-mass progenitor scenario (~$10\,M_\odot$) and implications for the late-time infrared luminosity driven by forward-shock heating.

Abstract

The evolution of dust in core-collapse supernovae (SNe), in general, is poorly constrained owing to a lack of infrared observations after a few years from explosion. Most theories of dust formation in SNe heavily rely only on SN 1987A. In the last two years, the James Webb Space Telescope (JWST) has enabled us to probe the dust evolution in decades-old SNe, such as SN 2004et, SN 2005ip, and SN 1980K. In this paper, we present two decades of dust evolution in SN 2005af, combining early-time infrared observations with Spitzer Space Telescope and recent detections by JWST. We have used a chemical kinetic model of dust synthesis in SN ejecta to develop a template of dust evolution in SN 2005af. Moreover, using this approach, for the first time, we have separately quantified the dust formed in the pre-explosion wind that survived after the explosion, and the dust formed in the metal-rich SN ejecta post-explosion. We report that in SN 2005af, predominantly carbon-rich dust formed in the ejecta, with a total mass of at least 0.02 Msun. In the circumstellar medium, the surviving oxygen-rich dust amounts to about 0.003-0.006 Msun, yielding a total dust mass of at least 0.025 Msun.

Figures (9)

• Figure 1: Left: Fluxes for the B (0.435 $\mu$m), g (0.477 $\mu$m), V (0.538 $\mu$m), r (0.622 $\mu$m), and i (0.761 $\mu$m) bands of SN 2005af are presented for the epochs (day 92 to day 163 post-explosion) covered by the CSP-I anderson_2024. Middle: The best-fit light curve model, where the parameters are given in Table \ref{['tab:table_lightcurve']}. Right: Two high-resolution optical spectra by Keck/LRIS obtained at day 92 post-explosion, and also at day 6322 post-explosion.
• Figure 2: The input conditions for dust-formation modeling in SN 2005af are presented. Elemental abundances (left), gas densities at day 100 (center), and gas temperatures (right) are derived using the formalism adopted by sarangi_2022b and the SN 2005af ejecta parameters derived in Section \ref{['sec_model']} (see Table \ref{['tab:table_lightcurve']}). The abundances and densities are shown in velocity space. The evolution of gas temperature is shown as a function of time for the O/Si, O/C, and He/C layers.
• Figure 3: Top: The composition and evolution of dust in SN 2005af, derived from the dust-formation model, is presented. O-rich dust, namely silicates and alumina and C-rich dust, namely amorphous carbon and silicon carbide, are considered. The model suggests steady growth of O-rich dust between days 400 and 800 post-explosion. Amorphous carbon dust forms at a rapid rate after 1100 days, and it becomes the most abundant dust component in the ejecta. Based on this study, we suggest that in SN 2005af, the ejecta are predominantly C-rich in dust. Bottom: The suggested distribution of dust within the ejecta of SN 2005af is shown for day 600, when dust formation has just begun, and for day 2900, when the formation of dust is already saturated. It is evident that O-rich dust is likely to form in the inner regions, while C-rich dust forms in the outer parts of the He core.
• Figure 4: The model predictions for the mass of molecules CO and SiO as a function of post-explosion time in the ejecta of SN 2005af. SiO molecules are considered a tracer and precursor of silicate dust formation sar13, while CO molecules remain as the most abundant molecule in the gas.
• Figure 5: Left and Middle: Spitzer IRAC images of SN 2005af taken on February 2006 (458 days post-explosion) and August 2008 (1363 days post-explosion) Szalai13Right: JWST/MIRI image of SN 2005af taken in July 2023 (6826 days post-explosion) in filter band F1500W.