标题： 裸奇星的电磁信号 显示英文标题

标题： Electromagnetic signals from bare strange stars

摘要： 晶体颜色超导相被认为对于足够大的奇异夸克质量值而言，是去禁闭夸克物质的基态。 这一相具有一个显著的性质，即比任何已知材料都更坚硬。 因此，它可以承受极大的剪切应力，并支持大振幅的扭转振动。 如果奇异星拥有晶体颜色超导外壳，那么这些扭转振动可能会导致可观察到的电磁信号。 事实上，考虑到一个简单的奇异星裸夸克物质表面模型，结果表明，在距离星体表面约十费米厚的狭窄壳层内会局部化一个正电荷。 为了中和夸克的正电荷，所需的电子会溢出到星体外部，形成一个数百费米厚的电磁束缚大气层。 当一个扭转振动被激发时，例如由恒星脉动引起，正电荷将以典型的千赫兹频率振荡：对于外壳厚度约为恒星半径十分之一的情况，频率为几千赫兹；而对于外壳厚度约为恒星半径十分之九的情况，频率可达到数百赫兹。 如果星壳厚度达到数厘米，可以达到高达几吉赫兹的更高频率。 我们通过考虑振荡磁偶极子的发射来估算辐射功率，发现其功率相当大，对于薄壳层，约为$10^{45}$毫尔焦耳/秒。 相关的弛豫时间非常不确定，根据壳层厚度的不同，其范围从微秒到分钟不等。 部分辐射光子会被电子大气吸收，但星体应能发出相当数量的光子。 显示英文摘要

摘要： The crystalline color superconducting phase is believed to be the ground state of deconfined quark matter for sufficiently large values of the strange quark mass. This phase has the remarkable property of being more rigid than any known material. It can therefore sustain large shear stresses, supporting torsional oscillations of large amplitude. The torsional oscillations could lead to observable electromagnetic signals if strange stars have a crystalline color superconducting crust. Indeed, considering a simple model of strange star with a bare quark matter surface, it turns out that a positive charge is localized in a narrow shell about ten Fermi thick beneath the star surface. The electrons needed to neutralize the positive charge of quarks spill in the star exterior forming an electromagnetically bounded atmosphere hundreds of Fermi thick. When a torsional oscillation is excited, for example by a stellar glitch, the positive charge oscillates with typical kHz frequencies, for a crust thickness of about one-tenth of the stellar radius, to hundreds of Hz, for a crust thickness of about nine-tenths of the stellar radius. Higher frequencies, of the order of few GHz, can be reached if the star crust is of the order of few centimeters thick. We estimate the emitted power considering emission by an oscillating magnetic dipole, finding that it can be quite large, of the order of $10^{45}$ erg/s for a thin crust. The associated relaxation times are very uncertain, with values ranging between microseconds and minutes, depending on the crust thickness. The radiated photons will be in part absorbed by the electronic atmosphere, but a sizable fraction of them should be emitted by the star.