Magnetic Rayleigh–Taylor instability in radiative flows

Abstract

We present a linear analysis of the radiative Rayleigh-Taylor (RT) instability in the presence of magnetic field for both optically thin and thick regimes. When the flow is optically thin, magnetic field not only stabilizes perturbations with short wavelengths, but also growth rate of the instability at long wavelengths is reduced compared to a nonmagnetized case. Then, we extend our analysis to the optically thick flows with a conserved total specific entropy and properties of the unstable perturbations are investigated in detail. Growth rate of the instability at short wavelengths is suppressed due to the presence of the magnetic field, however, growth rate is nearly constant at long wavelengths because of the radiation field. Since the radiative bubbles around massive protostars are subject to the RT instability, we also explore implications of our results in this context. In the nonmagnetized case, the growth time-scale of the instability for a typical bubble is found less than one thousand years which is very short compared to the typical star formation time-scale. Magnetic field with a reasonable strength significantly increases the growth time-scale to more than hundreds of thousands years. The instability, furthermore, is more efficient at large wavelengths, whereas in the non-magnetized case, growth rate at short wavelengths is more significant.

The Origin of Massive Stars: The Inertial-inflow Model

“…Krumholz et al 2005a;Keto 2007;Krumholz et al 2009;Kuiper et al 2011;Klassen et al 2016). Radiative bubbles around massive protostars cannot prevent the accretion of the infalling gas onto the star-disk system, because such bubbles are Rayleigh-Taylor unstable at early times (Rosen et al 2016) and the instability is expected to occur even in the magnetized case, though with a longer growth time-scale (Yaghoobi & Shadmehri 2018). Although the precise role of the various radiative feedback mechanisms remains difficult to quantify, here we focus on the origin of massive stars, that is the initial conditions responsible for their creation, and on the source and timescale of the accretion process, neglecting radiative feedback.…”

Ionising Feedback Effects on Star Formation in Globular Clusters with Multiple Stellar Populations

“…Thus the cluster is not initially in direct contact with the ISM as the region inside the hot bubble (𝑅 < 𝑅 eq ) is filled with a low-density gas (𝜌 ∼ 10 −31 g cm −3 ) formed by SNe ejecta and is in hydrostatic equilibrium with the cluster. By ignoring the dynamical instabilities of the bubble such as radiative Rayleigh-Taylor instability (Jacquet & Krumholz 2011;Yaghoobi & Shadmehri 2018), we can assume that the cluster traverses the radius of 𝑅 eq and arrives at the interface of the ISM at time 𝑡 I , after which it starts accreting pristine gas from the ISM. In our setup, it is assumed that the relative speed of the cluster with respect to the ISM is 23 km s −1 and remains constant.…”

Ionizing feedback effects on star formation in globular clusters with multiple stellar populations

“…Thus the cluster is not initially in direct contact with the ISM as the MNRAS 517, 4175-4186 (2022) region inside the hot bubble ( R < R eq ) is filled with a low-density gas ( ρ ∼ 10 −31 g cm −3 ) formed by SNe ejecta and is in hydrostatic equilibrium with the cluster. By ignoring the dynamical instabilities of the bubble, such as RT Rayleigh-Taylor instability (Jacquet & Krumholz 2011 ;Yaghoobi & Shadmehri 2018 ), we can assume that the cluster traverses the radius of R eq and arrives at the interface of the ISM at time t I , after which it starts accreting pristine gas from the ISM. In our setup, it is assumed that the relative speed of the cluster with respect to the ISM is 23 km s −1 and remains constant.…”