Predicting the Evolutionary Descendents of Sequence E Stars

TL;DR

This paper uses Monte Carlo simulations to estimate that about 10-16% of planetary nebula nuclei are short-period binaries resulting from common envelope events of sequence E red giants.

Contribution

It introduces a simulation-based method to predict the fraction of post-common envelope binaries among planetary nebulae nuclei based on observed sequence E binary frequencies.

Findings

10-16% of planetary nebulae nuclei are post-CE binaries.

Sequence E binaries are key to understanding binary evolution leading to planetary nebulae.

Monte Carlo simulation effectively predicts binary fractions in stellar evolution.

Abstract

Sequence E variables are close binary red giants that show ellipsoidal light variations. They are likely to terminate their red giant evolution by a common envelope (CE) event when the red giant fills its Roche lobe, and produce close binary Planetary Nebulae (PNe). We made a Monte Carlo simulation to predict the fraction of Planetary Nebulae Nuclei (PNNe) that are post-CE binaries, using the observed frequency of sequence E binaries in the LMC to normalize our calculations. We find that 10-16% of PNNe should be short period, post-CE binaries.