English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We study the mass fallback rate of tidally disrupted stars on marginallybound and unbound orbits around a supermassive black hole (SMBH) by performingthree-dimensional smoothed particle hydrodynamic (SPH) simulations with threekey parameters: the star is modeled by a polytrope with two different indexes($n=1.5$ and $3$). The stellar orbital properties are characterized by fiveorbital eccentricities ranging from $e=0.98$ to $1.02$ and five differentpenetration factors ranging from $\beta=1$ to $3$, where $\beta$ represents theratio of the tidal disruption to pericenter distance radii. We derive analyticformulae for the mass fallback rate as a function of the stellar densityprofile, orbital eccentricity, and penetration factor. Moreover, two criticaleccentricities to classify tidal disruption events (TDEs) into five differenttypes: eccentric ($e<e_{\rm crit,1}$), marginally eccentric ($e_{\rmcrit,1}\lesssim{e}<1$), purely parabolic ($e=1$), marginally hyperbolic($1<e<e_{\rm crit,2}$), and hyperbolic ($e\gtrsim{e_{\rm crit,2}}$) TDEs, arereevaluated as $e_{\rm crit,1}=1-2q^{-1/3}\beta^{k-1}$ and $e_{\rmcrit,2}=1+2q^{-1/3}\beta^{k-1}$, where $q$ is the ratio of the SMBH to stellarmasses and $0<k\lesssim2$. We find the asymptotic slope of the mass fallbackrate varies with the TDE type. The asymptotic slope approaches $-5/3$ forparabolic TDEs, is steeper for marginally eccentric TDEs, and is flatter formarginally hyperbolic TDEs. The mass fallback rates of the marginally eccentricTDEs are much larger than the parabolic TDE case, while those of marginallyhyperbolic TDEs are much smaller. Marginally unbound TDEs could be an origin ofa very low density gas disk around a dormant SMBH.

Tidal Disruption Flares from Stars on Marginally Bound and Unbound Orbits