The development of a new generation of theoretical models for tidaldisruptions is timely, as increasingly diverse events are being captured insurveys of the transient sky. Recently, Gezari et al. reported a discovery of anew class of tidal disruption events: the disruption of a helium-rich stellarcore, thought to be a remnant of a red giant (RG) star. Motivated by thisdiscovery and in anticipation of others, we consider tidal interaction of an RGstar with a supermassive black hole (SMBH) which leads to the stripping of thestellar envelope and subsequent inspiral of the compact core toward the blackhole. Once the stellar envelope is removed the inspiral of the core is drivenby tidal heating as well as the emission of gravitational radiation until thecore either falls into the SMBH or is tidally disrupted. In the case of tidaldisruption candidate PS1-10jh we find that there is a set of orbital solutionsat high eccentricities in which the tidally stripped hydrogen envelope isaccreted by the SMBH before the helium core is disrupted. This places the RGcore in a portion of parameter space where strong tidal heating can lift thedegeneracy of the compact remnant and disrupt it before it reaches the tidalradius. We consider how this sequence of events explains the puzzling absenceof the hydrogen emission lines from the spectrum of PS1-10jh and gives rise toits other observational features.
展开▼