We study rotating hybrid stars, with a particular emphasis on the effect of fast spin on the deconfinement phase transition in their interiors. We demonstrate the impact of increasing rotational frequencies on the maximum gravitational mass, central energy densities of compact stars, and the rise of the nonaxisymmetric instability. Utilizing observational data from the fastest-spinning millisecond pulsars with measured masses, we constrain the properties of hybrid stars and the onset of quark matter within compact star interiors.
We also revise the previously proposed empirical relation between the Kepler frequency, gravitational mass, and radius of non-rotating NSs, obtained based on the assumption that all NSs, up to the heaviest, are nucleonic. We show how the phase transition to the quark phase alters this relation and, consequently, the constraints on the dense matter equation of state (EoS). Our findings reveal that incorporating the hybrid EoS has significant implications for the constraints on the properties of strongly interacting matter and NSs.
Organized by: Catarina Cosme