Finite, Intense Accretion Bursts from Tidal Disruption of Stars on Bound Orbits

By K. Hayasaki, Nicholas C. Stone, Abraham Loeb. 2012

159 citations recorded by the source corpus.

We study accretion processes for tidally disrupted stars approaching supermassive black holes on bound orbits, by performing three dimensional Smoothed Particle Hydrodynamics simulations with a pseudo-Newtonian potential. We find that there is a critical value of the orbital eccentricity below which all the stellar debris remains bound to the black hole. For high but sub-critical eccentricities, all the stellar mass is accreted onto the black hole in a finite time, causing a significant deviation from the canonical t 5/3 mass fallback rate. When a star is on a moderately eccentric orbit and its pericenter distance is deeply inside the tidal disruption radius, there can be several orbit crossings of the debris streams due to relativistic precession. This dissipates orbital energy in shocks, allowing for rapid circularization of the debris streams and formation of an accretion disk. The resultant accretion rate greatly exceeds the Eddington rate and differs strongly from the canonical rate of t 5/3 . By contrast, there is little dissipation due to orbital crossings for the equivalent simulation with a purely Newtonian potential. This shows that general relativistic precession is crucial for accretion disk formation via circularization of stellar debris from stars on moderately eccentric orbits.

Subfields: Astronomy and Astrophysics, Biomedical Engineering

View Paper: https://www.semanticscholar.org/paper/b35ebd5219eb255364946dc6c3ccb6c4e3fd098e

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Biomedical Engineering

Citations in the corpus

Rates of stellar tidal disruption as probes of the supermassive black hole mass function (2014, background): “TDE debris circularization is not yet well understood, but of the two existing models for this process, both relativistic precession (Hayasaki et al. 2013) and hydrodynamic compression at pericenter (Guillochon et al. 2014) depend sensitively on β.”
Weighing Black Holes Using Tidal Disruption Events (2018, background): “This requires that the mass–energy distribution remain frozen until it begins to radiate, which can be accomplished through rapid circularization (Hayasaki et al. 2013; Guillochon & Ramirez-Ruiz 2015b).”
Disc formation from tidal disruptions of stars on eccentric orbits by Schwarzschild black holes (2015, methodology): “This is an improvement compared to most previous investigations that used an approximate treatment of this effect (Ramirez-Ruiz & Rosswog 2009; Hayasaki et al. 2013; Guillochon et al. 2014).”
A bright year for tidal disruptions (2015, background): “This could occur if a sub-population of TDEs arise from very tightly bound stellar orbits (Hayasaki et al. 2013), or if the interaction between misaligned BH spin and tidal compression in a high β event could dramatically increase Et (Stone et al. 2013).”
Circularization of Tidally Disrupted Stars around Spinning Supermassive Black Holes (2015, methodology): “…have shown that the pericentre shift of the stellar debris plays an essential role in quickly forming an accretion disk around a non-spinning SMBH, because it leads to debris orbit self-intersections, which dissipate energy in shocks and cause rapid circularization (Hayasaki et al. 2013).”
PS1-10jh: THE DISRUPTION OF A MAIN-SEQUENCE STAR OF NEAR-SOLAR COMPOSITION (2013, background): “The thinness of the stream 4 Guillochon, Manukian, Ramirez-Ruiz is also noted in other hydrodynamical simulations in which the mass ratio is large (Rosswog et al. 2009; Hayasaki et al. 2013).”
ASASSN-14ae: a tidal disruption event at 200 Mpc (2014, background): “The duration of a TDE can be truncated by putting the star on an orbit bound to the black hole (Hayasaki et al. 2013), but this necessarily implies that a larger fraction of the stellar mass is on bound orbits and so should enhance the total energy release.”
GENERAL RELATIVISTIC HYDRODYNAMIC SIMULATION OF ACCRETION FLOW FROM A STELLAR TIDAL DISRUPTION (2015, background): “General relativistic precession of the elliptical orbits’ apsidal orientation might help (Cannizzo et al. 1990; Hayasaki et al. 2013), but when the star’s pericenter is several tens of Rg or more, the precession angle is not great enough to engender shocks near Rp strong enough to dissipate a large…”