اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدCondensation of dust in the ejecta of type II-P supernovae
119
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Aims: We study the production of dust in Type II-P supernova by coupling the gas-phase chemistry to the dust nucleation and condensation phases. We consider two supernova progenitor masses with homogeneous and clumpy ejecta to assess the chemical type and quantity of dust that forms. Grain size distributions are derived as a function of post-explosion time. Methods: The chemistry of the gas phase and the simultaneous formation of dust clusters are described by a chemical network. The formation of key species (CO, SiO) and dust clusters of silicates, alumina, silica, metal carbides and sulphides, pure metals, and amorphous carbon is considered. The master equations describing the chemistry of the nucleation phase are coupled to a dust condensation formalism based on Brownian coagulation. Results: Type II-P supernovae produce dust grains of various chemical compositions and size distributions as a function of time. The grain size distributions gain in complexity with time, are slewed towards large grains, and differ from the usual MRN power-law distribution used for interstellar dust. Gas density enhancements in the form of clumps strongly affect the dust chemical composition and the grain size distributions. Silicates and pure metallic grains are highly dependent on clumpiness. Specifically, clumpy ejecta produce grains over 0.1 micron, and the final dust mass reaches 0.14 Msun. Conversely, carbon and alumina dust masses are controlled by the mass yields of alumina and carbon in the zones where the dust is produced. Several dust components form in the ejecta and the total dust mass gradually builds up over a time span of 3 to 5 years post-outburst. This gradual growth provides a possible explanation for the discrepancy between the small dust masses formed at early post-explosion times and the high dust masses derived from recent observations of supernova remnants.
قيم البحث
اقرأ أيضاً
We study the formation of molecules and dust clusters in the ejecta of solar metallicity, Type II-P supernovae using a chemical kinetic approach. We follow the evolution of molecules and small dust cluster masses from day 100 to day 1500 after explos
ion. We consider stellar progenitors with initial mass of 12, 15, 19 and 25 Msun that explode as supernovae with stratified ejecta. The molecular precursors to dust grains comprise molecular chains, rings and small clusters of silica, silicates, metal oxides, sulphides and carbides, pure metals, and carbon, where the nucleation of silicate clusters is described by a two-step process of metal and oxygen addition. We study the impact of the 56Ni mass on the type and amount of synthesised dust. We predict that large masses of molecules including CO, SiO, SiS, O2, and SO form in the ejecta. We show that the discrepancy between the small dust masses detected at infrared wavelengths some 500 days post-explosion and the larger amounts of dust recently detected with Herschel in supernova remnants can be explained by the non-equilibrium chemistry linked to the formation of molecules and dust clusters in the ejected material. Dust gradually builds up from small (~10^{-5} Msun) to large masses (~5x 10^{-2} Msun) over a 5 yr period after explosion. Subsequent dust formation and/or growth is hampered by the shortage of chemical agents participating in the dust nucleation and the long time scale for accretion. The results highlight the dependence of the dust chemical composition and mass on the amount of 56Ni synthesised during the explosion. This dependence may partly explain the diversity of epochs at which dust forms in supernovae. More generally, our results indicate that type II-P supernovae are efficient but moderate dust producers with an upper limit on the mass of synthesised dust ranging from ~ 0.03 to 0.09 Msun.
We study the formation of dust in the expanding gas ejected as a result of a common envelope binary interaction. In our novel approach, we apply the dust formation model of Nozawa et al. to the outputs of the 3D hydrodynamic SPH simulation performed
by Iaconi et al., that involves a giant of 0.88~ms and 83~rs, with a companion of 0.6~ms placed on the surface of the giant in circular orbit. After simulating the dynamic in-spiral phase we follow the expansion of the ejecta for $simeq 18,000$~days. During this period the gas is able to cool down enough to reach dust formation temperatures. Our results show that dust forms efficiently in the window between $simeq 300$~days (the end of the dynamic in-spiral) and $simeq 5000$~days. The dust forms in two separate populations; an outer one in the material ejected during the first few orbits of the companion inside the primarys envelope and an inner one in the rest of the ejected material. We are able to fit the grain size distribution at the end of the simulation with a double power law. The slope of the power law for smaller grains is flatter than that for larger grains, creating a knee-shaped distribution. The power law indexes are however different from the classical values determined for the interstellar medium. We also estimate that the contribution to cosmic dust by common envelope events is not negligible and comparable to that of novae and supernovae.
We investigate the early-time light-curves of a large sample of 223 type II supernovae (SNe) from the Sloan Digital Sky Survey and the Supernova Legacy Survey. Having a cadence of a few days and sufficient non-detections prior to explosion, we constr
ain rise-times, i.e. the durations from estimated first to maximum light, as a function of effective wavelength. At restframe g-band (4722A), we find a distribution of fast rise-times with median of (7.5+/-0.3) days. Comparing these durations with analytical shock models of Rabinak and Waxman (2013); Nakar and Sari (2010) and hydrodynamical models of Tominaga et al. (2009), which are mostly sensitive to progenitor radius at these epochs, we find a median characteristic radius of less than 400 solar radii. The inferred radii are on average much smaller than the radii obtained for observed red supergiants (RSG). Investigating the post-maximum slopes as a function of effective wavelength in the light of theoretical models, we find that massive hydrogen envelopes are still needed to explain the plateaus of SNe II. We therefore argue that the SN II rise-times we observe are either a) the shock cooling resulting from the core collapse of RSG with small and dense envelopes, or b) the delayed and prolonged shock breakout of the collapse of a RSG with an extended atmosphere or embedded within pre-SN circumstellar material.
In order to understand the contribution of core-collapse supernovae to the dust budget of the early universe, it is important to understand not only the mass of dust that can form in core-collapse supernovae but also the location and rate of dust for
mation. SN 2005ip is of particular interest since dust has been inferred to have formed in both the ejecta and the post-shock region behind the radiative reverse shock. We have collated eight optical archival spectra that span the lifetime of SN 2005ip and we additionally present a new X-shooter optical-near-IR spectrum of SN 2005ip at 4075d post-discovery. Using the Monte Carlo line transfer code DAMOCLES, we have modelled the blueshifted broad and intermediate width H$alpha$, H$beta$ and He I lines from 48d to 4075d post-discovery using an ejecta dust model. We find that dust in the ejecta can account for the asymmetries observed in the broad and intermediate width H$alpha$, H$beta$ and He I line profiles at all epochs and that it is not necessary to invoke post-shock dust formation to explain the blueshifting observed in the intermediate width post-shock lines. Using a Bayesian approach, we have determined the evolution of the ejecta dust mass in SN 2005ip over 10 years presuming an ejecta dust model, with an increasing dust mass from ~10$^{-8}$ M$_{odot}$ at 48d to a current dust mass of $sim$0.1 M$_{odot}$.
We study a sample of 23 Type II Plateau supernovae (SNe II-P), all observed with the same set of instruments. Analysis of their photometric evolution confirms that their typical plateau duration is 100 days with little scatter, showing a tendency to
get shorter for more energetic SNe. The rise time from explosion to plateau does not seem to correlate with luminosity. We analyze their spectra, measuring typical ejecta velocities, and confirm that they follow a well behaved power-law decline. We find indications of high-velocity material in the spectra of six of our SNe. We test different dust extinction correction methods by asking the following -- does the uniformity of the sample increase after the application of a given method? A reasonably behaved underlying distribution should become tighter after correction. No method we tested made a significant improvement.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
