Rapid cooling of Cassiopeia A as a phase transition in dense QCD

Institute for Theoretical Physics, J. W. Goethe University, 60438 Frankfurt am Main, Germany
e-mail: sedrakian@th.physik.uni-frankfurt.de

Received: 21 March 2013
Accepted: 19 June 2013

Abstract

We present a model of the compact star in Cassiopea A that accounts for its unusually fast cooling behavior. This feature is interpreted as an enhancement in the neutrino emission triggered by a transition from a fully gapped, two-flavor, color-superconducting phase to a crystalline phase or an alternative gapless, color-superconducting phase. By fine-tuning a single parameter – the temperature of this transition – a specific cooling scenario can be selected that fits the Cas A data. Such a scenario requires a massive M ~ 2   M_⊙ star and is, therefore, distinctive from models invoking canonical 1.4 M_⊙ mass star with nucleonic pairing alone.