The Decline and Fall of the Youngest Planetary Nebula

TL;DR

This paper documents the rapid evolution and fading of the Stingray Nebula, highlighting its transition into a recombination nebula over two decades based on Hubble observations.

Contribution

It provides the first detailed, long-term observational analysis of the nebula's morphological and emission-line changes since its discovery.

Findings

Significant decrease in nebular emission-line fluxes

Change in nebula shape observed over 20 years

Transition to a recombination nebula confirmed

Abstract

The Stingray Nebula, aka Hen3-1357, appeared for the first time in 1990 when bright nebular lines and radio emission that had not been observed before were unexpectedly discovered (Parthasarathy et al. 1993). In the ensuing years the nebula faded precipitously. We report changes in shape and large decreases in its nebular emission-line fluxes based on well-calibrated images obtained by the Hubble Space Telescope in 1996 and 2016. Hen3-1357 is now a "recombination nebula".