Color Superconductivity in Quark Stars: Powering Gamma Ray Bursts

A two flavors color superconductive phase has been suggested as a plausible state of quark matter at high density. An intrinsic property of such a state is the generation of light particles which immediately decay into photons. Here, we explore the possibility for such a state to set in at the surface of a quark star where temperatures below Tc (the critical temperature above which color superconductivity cannot exist) are first achieved following neutrino cooling. The generated photons, acquiring a black body distribution, allow us to develop a model which can quantitatively account for many of the observed features of gamma ray bursts. Among them, (i) the episodic activity of the engine (multiple and random shell emission); (ii) the two distinct categories of the bursts (∼ 1 s and ∼ 16 s duration); (iii) shell-shell collision dynamics and energetics (0 < Γshell < 2×10 5 and ρshell ∝ Γ −2 shell); (iv) a peak duration vs energy dependence tp ∝ E −0.5 p , and (v) gamma ray burst energy range, 8× 10 49 ergs < EGRB < 1.6× 10 54 ergs. We establish a possible link between gamma ray bursts and color superconductivity. We show that bursts data can be used as a new tool to (a) derive the Mass-Radius plane for quark stars and (b) map the Quantum-Chromodynamics phase diagram in a regime impossible with current earth-based facilities. Our model, constrained by BATSE observations, favors Tc ≃ 15 MeV. We conclude that the superconductive gap is larger than 15 MeV for densities few times nuclear matter density. Subject headings: dense matter – color superconductivity – stars: compact – stars: Gamma ray bursts