Rescaling strange-cluster stars and its implications on gravitational-wave echoes

作者：Chen Zhang, Yong Gao, Cheng-Jun Xia, Renxin Xu · 发表于：Physical review. D/Physical review. D. · 年份：2023 · DOI：10.1103/physrevd.108.063002 · 被引用次数：13 · 研究领域：Pulsars and Gravitational Waves Research、Cold Atom Physics and Bose-Einstein Condensates、High-pressure geophysics and materials

Solid states of strange-cluster matter called strangeon matter can form strangeon stars that are highly compact. We show that strangeon matter and strangeon stars can be recast into dimensionless forms by a simple reparametrization and rescaling, through which we manage to maximally reduce the number of degrees of freedom. With this dimensionless scheme, we find that strangeon stars are generally compact enough to feature a photon sphere that is essential to foster gravitational-wave (GW) echoes. Rescaling the dimension back, we illustrate its implications on the expanded dimensional parameter space, and calculate the characteristic GW echo frequencies associated with strangeon stars, showing that the minimum echo frequency is $\ensuremath{\sim}8\text{ }\text{ }\mathrm{kHz}$ for empirical parameter space that satisfies the GW170817 constraint, and can reduce to $\mathcal{O}(100)$ Hertz at the extended limit.