Construction of a Penrose Diagram for a Spatially Coherent Evaporating Black Hole

TL;DR

This paper constructs a Penrose diagram for an evaporating black hole, illustrating its causal structure and coordinate features as the black hole loses mass and transitions to flat space.

Contribution

It provides a detailed Penrose diagram for a steady-evaporating black hole, highlighting coordinate behaviors and causal structure changes during evaporation.

Findings

The diagram shows the evolution of the event horizon during evaporation.

Coordinate anomalies are identified and explained.

The final state is Minkowski space after black hole evaporation.

Abstract

A Penrose diagram is constructed for an example black hole that evaporates at a steady rate as measured by a distant observer, until the mass vanishes, yielding a final state Minkowski space-time. Coordinate dependencies of significant features, such as the horizon and coordinate anomalies, are clearly demonstrated on the diagram. The large-scale causal structure of the space-time is briefly discussed.