Surveying Planetary Nebulae Central Stars for Close Binaries: Constraining Evolution of Central Stars Based on Binary Parameters

TL;DR

This survey reviews recent findings on close binary central stars of planetary nebulae, exploring their impact on nebular shaping, evolution, and binary fractions, and clarifies their evolutionary stages.

Contribution

It compiles and analyzes recent observational data to better understand the role of close binaries in planetary nebula evolution and morphology.

Findings

Close binary central stars influence nebular shaping.

Proto-planetary nebulae are not precursors of close binary planetary nebulae.

The total binary fraction among central stars is significant.

Abstract

The increase in discovered close binary central stars of planetary nebulae is leading to a sufficiently large sample to begin to make broader conclusions about the effect of close binary stars on common envelope evolution and planetary nebula formation. Herein I review some of the recent results and conclusions specifically relating close binary central stars to nebular shaping, common envelope evolution off the red giant branch, and the total binary fraction and double degenerate fraction of central stars. Finally, I use parameters of known binary central stars to explore the relationship between the proto-planetary nebula and planetary nebula stages, demonstrating that the known proto-planetary nebulae are not the precursors of planetary nebulae with close binary central~stars.