The Unexpectedly Small Impact of General Relativistic Effects on Parabolic and Deeply Penetrating Tidal Disruption Event

Stellar tidal disruption event (TDE) is thought to be influenced by general relativistic (GR) effects, which modify the star's orbit and impact its subsequent evolution. To examine such effects, we simulate a deeply penetrating, parabolic TDE involving a main-sequence star and a supermassive black hole, following both the disruption and fallback phases using the code harm3D. GR-induced pericenter precession drives strong stream-stream collisions, which rapidly dissipate orbital energy and reduce the gas eccentricity near the pericenter to ~0.3–0.4. These collisions power a bolometric luminosity of ~10⁴³ erg s⁻¹, trigger adiabatic gas expansion that increase the photospheric radius to 10¹⁴ cm with an effective temperature of ~10⁴ K. Thereafter, stream-stream collisions broaden the angular momentum distribution, widen the range of gas orbital pericenters, and shift the stream self-crossing position to larger radii. The deflected stream then spans a broader azimuthal angle, while vertically thickens by nozzle shock heating, reducing the stream self-crossing strength. The incoming stream remains thin and dense enough to penetrate the geometrically thick, eccentric disk around the black hole with minimal interaction, making stream-disk interactions largely ineffective. Nozzle shocks become the primary site of orbital energy dissipation and angular momentum transport that drive accretion onto the black hole, but fail to fully circularize the debris. The gas circularization efficiency then declines to ~10⁻². These results suggest that while GR effects strongly influence early-time dynamics and emission, they may have only a limited impact on the long-term evolution of TDEs.