Cooling of hypernuclear compact stars

Understand

We study the thermal evolution of hypernuclear compact stars constructed from covariant density functional theory of hypernuclear matter and parameterizations which produce sequences of stars containing two-solar-mass objects.

• For the input in the simulations, we solve the Bardeen-Cooper-Schrieffer gap equations in the hyperonic sector and obtain the gaps in the spectra of $\Lambda$, $\Xi^0$ and $\Xi^-$ hyperons.
• For the models with masses $M/M_{\odot} \ge 1.5$ the neutrino cooling is dominated by hyperonic direct Urca processes in general.
• In the low-mass stars the $(\Lambda p)$ plus leptons channel is the dominant direct Urca process, whereas for more massive stars the purely hyperonic channels $(\Sigma^-\Lambda)$ and $(\Xi^-\Lambda)$ are dominant.