Formation, distribution, and IR emission of dust in the clumpy ejecta of Type II-P core-collapse supernovae, in isotropic and anisotropic scenarios

Abstract

Large discrepancies are found between observational estimates and theoretical predictions when exploring the characteristics of dust formed in the ejecta of a core-collapse supernovae. We revisit the scenario of dust production in typical supernova ejecta in the first 3000 days after explosion, with an improved understanding of the evolving physical conditions and the distribution of the clumps. The generic, nonuniform distribution of dust within the ejecta was determined and using that, the relevant opacities and fluxes were calculated. The dependence of the emerging fluxes on the viewing angle was estimated for an anisotropic, ellipsoidal geometry of the ejecta that imitate SN 1987A. We model the He core from the center to its outer edge as 450 stratified, clumpy, annular shells, uniquely identified by their distinct velocities and characterized by their variations in abundances, densities, and gas and dust temperatures. We find that the formation of dust starts between day 450 and day 550 post-explosion, and it continues until about day 2800, although the first 1600 days are the most productive. The total dust mass evolves from ∼ 10 −5 M at day 500 to 10 −3 M at day 800, finally saturating at about 0.06 M . The masses of the O-rich dust (silicates, alumina) dominates the C-rich dust (amorphous carbon, silicon carbide) at all times; the formation of carbon dust is delayed beyond 2000 days post-explosion. We show that the opacities are largest between days 800 and 1600, and the characteristic spectral features of O-rich dust species are suppressed at those times. The fluxes emerging along the smallest axes of the ellipsoidal ejecta are found to be the most obscured, while a viewing angle between 16 to 21 • with that axis appears to be in best agreement with the fluxes from SN 1987A at days 615 and 775.

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

“…The dust formation zone within the metal-rich ejecta is expected to be confined within 5000 km s −1 (Truelove & McKee 1999;Maguire et al 2012;Sarangi 2022), which is consistent with the velocity profile in Figure 2. These velocities correspond to a radius of ∼ 2.8 × 10 17 cm and 7.8 × 10 16 cm for SN 2004et and SN 2017eaw, respectively.…”

“…Interestingly, we find that the total IR luminosity of SN 2004et is higher than the luminosity of SN 2017eaw, even though the latter is younger and is expected to have a stronger forward shock luminosity. This may indicate that the younger SN 2017eaw, being more compact, is optically thick in the mid-IR, as some theoretical studies suggest (Dwek et al 2019;Sarangi 2022). On the other hand, it may also indicate that the silicate-rich dust in the ejecta of SN 2017eaw is expanding at a smaller velocity (compared to carbon dust in SN 2004et), so a smaller fraction of the forward shock luminosity is absorbed here.…”

“…In this study, we have also chosen Mg-silicates and/or amorphous carbon as our dust composition. The abosorption and emission properties of these grains are obtained from Draine & Li (2007) and Zubko et al (2004) for silicates and amorphous carbon respectively (see Sarangi (2022) for the values of absorption coefficients 𝜅). Given that we are dealing with mid-IR data, the wavelengths are much larger than the expected sizes of grains; in this Rayleigh regime, grain sizes do not impact the emerging fluxes.…”

“…Therefore, we can expect that all the absorbed radiation will be reprocessed and radiated back in the IR. For SN 2004et, using the IR luminosity of 2.9 × 10 4 L and a dust temperature of ∼ 140 K, if we assume equilibrium of absorption and emission (Temim & Dwek 2013;Sarangi 2022), the approximate forward shock velocity can be calculated to be ∼ 10, 000 km s −1 . Comparing the IR luminosity to the forward shock luminosity (which is expected to be at least 10 40 ergs s −1 , suggested by Dessart & Hillier 2022), the velocity of the dusty ejecta can be found estimated as ∼ 3000 km s −1 , which matches well with the location of carbon-dust formation (Sarangi 2022).…”

Emission lines due to ionizing radiation from a compact object in the remnant of Supernova 1987A

“…However, the composition of the dust close to the center is likely to differ from that of the outer regions (10). Dust nucleation models have predicted that silicates dominate over carbon-rich dust in the central regions (43)(44)(45)(46), of which Mg 2 SiO 4 (forsterite) is expected to have the highest abundance. Observations of young SNRs have shown that silicates are the dominant type of dust (10).…”