论文标题
X射线背景中的人口III星形成：III。椭圆轨道引起的周期性辐射反馈和光度
Population III star formation in an X-ray background: III. Periodic radiative feedback and luminosity induced by elliptical orbits
论文作者
论文摘要
我们在不同的FUV和X射线背景中对流行III星形形成进行建模，包括来自Protostar的辐射反馈。我们证实了先前的结果，即中等的X射线背景增加了单位宇宙学量的POP III系统的数量，但是系统的质量和多重性却减少了。恒星质量函数也与先前的结果一致，我们确认了原始盘中恒星的向外迁移。我们发现，几乎所有的流行III星系都是分层的，即二进制的二进制组。通常，在原始盘的中心附近形成两个相等的恒星并向外迁移。在这些恒星周围，迷你碟片碎片形成了也向外迁移的二进制物。恒星也可能在系统的Lagrange点L4/L5处形成。之后，由于较大的多样性，恒星形成变得更加随机，当从圆盘上迅速弹出时，零金属性低质量恒星会形成。光盘中的恒星通常具有偏心轨道，导致其积聚率和亮度的定期调节。在折点上，由于强大的积聚，恒星可以进入一个红色的阶段，在光条带上几乎达到了爱丁顿的光度（$ m _ {\ rm ab} \ sim 34 $ 34 $，价格为$ 100〜m_ {odot} $ star $ star $ z = 6 $）。在此阶段，如果通过重力透镜充分放大，则可以直接观察到恒星而不是其树干线。在我们的模拟中，$ \ sim 10,000 $ au的分离和许多流行III星二进制物的高偏心率是IMBH合并的有利参数 - 以及引力波排放 - 通过田间星星的轨道激发。
We model Pop III star formation in different FUV and X-ray backgrounds, including radiation feedback from protostars. We confirm previous results that a moderate X-ray background increases the number of Pop III systems per unit cosmological volume, but masses and multiplicities of the system are reduced. The stellar mass function also agrees with previous results, and we confirm the outward migration of the stars within the protostellar discs. We find that nearly all Pop III star systems are hierarchical, i.e., binaries of binaries. Typically, two equal-mass stars form near the centre of the protostellar disc and migrate outward. Around these stars, mini-discs fragment forming binaries that also migrate outward. Stars may also form at Lagrange points L4/L5 of the system. Afterward, star formation becomes more stochastic due to the large multiplicity, and zero-metallicity low-mass stars can form when rapidly ejected from the disc. Stars in the disc often have eccentric orbits, leading to a periodic modulation of their accretion rates and luminosities. At the pericenter, due to strong accretion, the star can enter a red-supergiant phase reaching nearly Eddington luminosity in the optical bands ($m_{\rm AB} \sim 34$ for a $100~M_{odot}$ star at $z=6$). During this phase, the star, rather than its nebular lines, can be observed directly by JWST, if sufficiently magnified by a gravitational lens. The $\sim 10,000$ AU separations and high eccentricities of many Pop III star binaries in our simulations are favorable parameters for IMBH mergers - and gravitational waves emission - through orbital excitation by field stars.
