Dust destruction in bubbles driven by multiple supernovae explosions

TL;DR

This study shows that dust destruction by multiple clustered SNe forms bubbles in which dust processing diverges from the isolated-SN case. Using 3D hydrodynamic simulations with a dust-coupled gas framework, the authors track dust destruction across a range of cluster masses and SN intervals in both homogeneous and clumpy media. They find that dust destruction saturates over time, with the saturation timescale $t_{sat}$ increasing with SN rate, and that the total dust destroyed per SN is much smaller than the naive sum of isolated SNe (roughly an order of magnitude lower, around $10\%$ of the isolated-SN value on average). In clumpy environments, the destruction efficiency can rise by factors of $\sim$1.5–4, but overall the ISM dust lifetime is still extended by about a factor of $\sim 10$ compared to isolated SN estimates, since low-mass clusters dominate the destruction budget. These results help reconcile the dust-budget crisis by highlighting the pivotal role of clustered SNe and ISM structure in regulating dust lifetimes and infrared signatures.

Abstract

Dust lifetime derived from an isolated supernova (SN) evolution in the interstellar medium is known to be an order of magnitude shorter than the time needed to replenish dust mass by its production in various Galactic sources. We show, using 3-D numerical hydrodynamical simulations, that destruction of dust in the case of multiple SNe in a star cluster is markedly different from that in an isolated SN. We find that the mass of dust destroyed in the bubble does not grow for a considerable time, while SNe continue to explode. This regime is attained at saturation timescale, which is proportional to SNe rate in cluster. We show that the mass of dust destroyed in bubble per SN decreases for higher SN rate. Thus, the destruction efficiency -- defined as the ratio of the the total mass of dust destroyed by clustered SNe to that destroyed by the same number of isolated SNe -- in bubbles evolved in a homogeneous medium drops for massive clusters, e.g. around clusters with $M_\ast > 4\times 10^4 M_\odot$ it is less $0.4$\%. For lower mass clusters, the efficiency is proportional to the average time delay between SNe. We found that each cluster with $M_\ast < 4\times 10^4 M_\odot$ destroys the same mass of dust as a single isolated SN. In a clumpy medium in bubbles formed around clusters with $M_\ast \sim 4\times 10^4 M_\odot$ and up to 4 times around $M_\ast \sim 8\times 10^5 M_\odot$. We argue that the interstellar dust swept up by multiple SNe almost completely survives in the shells of bubbles around such massive clusters. Therefore, the destruction of the interstellar dust is controlled by SNe in low-mass clusters. We point out that the interstellar dust lifetime for a given SN rate is at least a factor $\sim 10$ longer as compared to the estimates derived from an isolated SN. (abridged)

Figures (11)

• Figure 1: Mass of the bubble driven by multiple SNe explosions in a cluster. The color lines depict the evolution for different rates, of one SN per $\Delta t = 100$, 50, 30, 10 and 5 kyr.
• Figure 2: Mass of dust destroyed in the bubble for the models presented in Fig. \ref{['fig-mgas-evol']}. The brown points correspond to the saturation time according to eq. \ref{['eq-sat']}, whereas the grey points refer to the onset of radiative phase of bubbles ($\upsilon \sim 100$ km s$^{-1}$).
• Figure 3: The dust destruction efficiency, i.e. the ratio of the the total mass of dust destroyed by SNe in cluster to the value of dust destroyed by the same number of isolated SNe. The dash line follows $\Delta t/t_{lf,max}$, where $t_{lf,max} \sim 24$ Myr.
• Figure 4: Total mass of dust destroyed in the bubble driven by SNe with the rate one per $\Delta t = 10$ and 5 kyr (green and brown lines, respectively) in the medium with gas number density $n$.
• Figure 5: The $y=0$ plane slice of the gas density distribution in the bubble from clustered SNe in a clumpy medium with the average density $\langle\rho\rangle = 1~m_H$ g cm$^{-3}$ at the age $t=800$ kyr. Black circles roughly outline the forward shock at times $t=20,~60,~100,~200,~300,~440,~580$ and 800 kyr. Engulfed clumps being episodically impacted by upcoming shocks are seen to be deformed and compressed. At the same time, they are accelerated but because of compression they remain deep behind the forward shock.