Authors: K. Belczynski, G. Wiktorowicz, C. Fryer, D. Holz, V. Kalogera
Date: 7 Oct 2011
Abstract: There exist a wide range of masses and types of stars that form compact object remnants: white dwarfs, neutron stars, or black holes. The stellar mass distribution is smooth, covering the range 0.1-100 Msun. It is expected that the masses of the ensuing compact remnants correlate with the masses of their progenitor stars, and thus it is thought that the remnant masses should be smoothly distributed from the lightest white dwarfs to the heaviest black holes. However, this intuitive prediction is not borne out by observed data. In the rapidly growing population of remnants with determined masses, a striking mass gap has emerged at the boundary between neutron stars and black holes. The heaviest neutron stars reach a maximum of 2 Msun, while the lightest black holes are at least 5 Msun. At first this gap was attributed to a paucity of observations. However, with recent determinations of the masses for more than 20 black holes, the gap has remained intact and become a significant challenge to our understanding of compact object formation. Over a decade after this gap was initially noted, we offer the first insights into the physical processes that bifurcate the formation of remnants into lower mass neutron stars and heavier black holes. Combining the results of full stellar modeling with multidimensional hydrodynamic simulations of supernova explosions, we both explain the existence of the gap, and also put stringent constraints on the inner workings of the supernova explosion mechanism. In particular, we show that core-collapse supernovae are launched within 100-200 ms of the initial stellar collapse. This implies that the explosions are driven by Rayleigh-Taylor instabilities rather than the delayed standing accretion shock instabilities, resolving a major debate in the supernova community.
© M. Vallisneri 2012 — last modified on 2010/01/29
Tantum in modicis, quantum in maximis