Limits on mass outflow from optical tidal disruption events

TL;DR

This paper introduces a new method to estimate outflow mass and energy in optical tidal disruption events, revealing that observed outflows are more massive than stellar, challenging existing reprocessing models.

Contribution

It presents a novel approach to infer outflow properties from optical TDE observations, questioning current reprocessing explanations.

Findings

Outflows in optical TDEs are more massive than stellar masses.

Current models may underestimate outflow mass and energy.

Observed luminosity and temperature data are consistent with hydrodynamic estimates.

Abstract

The discovery of optical/UV tidal disruption events (TDEs) was surprising. The expectation was that, upon returning to the pericenter, the stellar-debris stream will form a compact disk that will emit soft X-rays. Indeed the first TDEs were discovered in this energy band. A common explanation for the optical/UV events is that surrounding optically-thick matter reprocesses the disk's X-ray emission and emits it from a large photosphere. If accretion follows the super-Eddington mass infall rate it would inevitably result in an energetic outflow, providing naturally the reprocessing matter. We describe here a new method to estimate, using the observed luminosity and temperature, the mass and energy of outflows from optical transients. When applying this method to a sample of supernovae our estimates are consistent with a more detailed hydrodynamic modeling. For the current sample of a few dozen optical TDEs the observed luminosity and temperature imply outflows that are significantly more massive than typical stellar masses, posing a problem to this common reprocessing picture.