TY - JOUR
T1 - Bubbles in planetary nebulae and clusters of galaxies
T2 - Instabilities at bubble' fronts
AU - Soker, Noam
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2004/5
Y1 - 2004/5
N2 - I study the stability of off-center low-density more or less spherical (fat) bubbles in clusters of galaxies and in planetary nebulae (PNs) to Rayleigh-Taylor (RT) instability. As the bubble expands and decelerates, the interface between the low-density bubble's interior and the dense shell formed from the accreted ambient medium is RT-stable. If, however, in a specific direction the density decreases such that this segment is accelerated by the pressure inside the bubble, then this accelerated region is RT-unstable. The outermost region, relative to the center of the system, is the most likely to become unstable because there the density gradient is the steepest. Using simple analytical analysis, I find that off-center fat bubbles in PNs are much less stable than in clusters. In PNs bubbles become unstable when they are very small relative to their distance from the center; they can be stabilized somewhat if the mass loss rate from the stellar progenitor decreases for a time, such that the negative density gradient is much shallower. In clusters fat bubbles become unstable when their size is comparable to their distance from the center. I discuss some implications of this instability in clusters and in PNs.
AB - I study the stability of off-center low-density more or less spherical (fat) bubbles in clusters of galaxies and in planetary nebulae (PNs) to Rayleigh-Taylor (RT) instability. As the bubble expands and decelerates, the interface between the low-density bubble's interior and the dense shell formed from the accreted ambient medium is RT-stable. If, however, in a specific direction the density decreases such that this segment is accelerated by the pressure inside the bubble, then this accelerated region is RT-unstable. The outermost region, relative to the center of the system, is the most likely to become unstable because there the density gradient is the steepest. Using simple analytical analysis, I find that off-center fat bubbles in PNs are much less stable than in clusters. In PNs bubbles become unstable when they are very small relative to their distance from the center; they can be stabilized somewhat if the mass loss rate from the stellar progenitor decreases for a time, such that the negative density gradient is much shallower. In clusters fat bubbles become unstable when their size is comparable to their distance from the center. I discuss some implications of this instability in clusters and in PNs.
KW - Galaxies: clusters: general
KW - ISM: jets and outflows
KW - Intergalactic medium
KW - Planetary nebulae: general
UR - http://www.scopus.com/inward/record.url?scp=1142267533&partnerID=8YFLogxK
U2 - 10.1016/j.newast.2003.12.003
DO - 10.1016/j.newast.2003.12.003
M3 - 文章
AN - SCOPUS:1142267533
VL - 9
SP - 285
EP - 290
JO - New Astronomy
JF - New Astronomy
SN - 1384-1076
IS - 4
ER -