The destruction of a star by the tides of a supermassive black hole (SMBH) powers a bright accretion flare, and the theoretical modeling of such tidal disruption events (TDEs) can provide a direct means of inferring SMBH properties from observations. Previously it has been shown that TDEs with β=r _t/r _p=1, where r _t is the tidal disruption radius and r _p is the pericenter distance of the star, form an in-plane caustic, or “pancake,” where the tidally disrupted debris is compressed into a one-dimensional line within the orbital plane of the star. Here we show that this result applies generally to all TDEs for which the star is fully disrupted, i.e., that satisfy β≳1. We show that the location of this caustic is always outside of the tidal disruption radius of the star and the compression of the gas near the caustic is at most mildly supersonic, which results in an adiabatic increase in the gas density above the tidal density of the black hole. As such, this in-plane pancake revitalizes the influence of self-gravity even for large β, in agreement with recent simulations. This finding suggests that for all TDEs in which the star is fully disrupted, self-gravity is revived post-pericenter, keeps the stream of debris narrowly confined in its transverse directions, and renders the debris prone to gravitational instability.

超大质量黑洞 (SMBH) 的潮汐对恒星的破坏为明亮的吸积耀斑提供动力，而此类潮汐破坏事件 (TDE) 的理论建模可以提供从观测中推断 SMBH 特性的直接方法。先前已经表明，具有β = r _t / r _p =1 的TDE ，其中r _t是潮汐中断半径，r _p是恒星的中心距离，形成平面内焦散或“薄饼”，其中潮汐干扰的碎片被压缩成恒星轨道平面内的一维线。在这里我们表明这个结果一般适用于所有恒星完全被破坏的TDE ，即满足β ≳1。我们表明，这种焦散的位置总是在恒星的潮汐破坏半径之外，并且焦散附近的气体压缩至多是轻微的超音速，这导致气体密度绝热增加超过了恒星的潮汐密度。黑洞。因此，即使对于大β，这种面内煎饼也能恢复自重的影响，与最近的模拟一致。这一发现表明，对于所有恒星被完全破坏的 TDE，自重在中心后恢复，使碎片流狭窄地限制在其横向上，并使碎片容易发生引力不稳定。