On the role of reduced wind mass-loss rate in enabling exoplanets to shape planetary nebulae

Ahlam Hegazi, Ealeal Bear, Noam Soker (Technion, Israel)

We use the stellar evolution code MESA-binary and follow the evolution of six exoplanets to determine their potential role in the future evolution of their parent star on the red giant branch (RGB) and on the asymptotic giant branch (AGB). We limit this study to planets with orbits that have semi-major axis of 1AU0.25, and having a parent star of mass M>1Mo. We find that the star HIP 75458 will engulf its planet HIP75458 b during its RGB phase. The planet will remove the envelope and terminate the RGB evolution, leaving a bare helium core of mass 0.4Mo that will evolve to form a helium white dwarf. Only in one system out of six, the planet beta Pic c will enter the envelope of its parent star during the AGB phase. For that to occur, we have to reduce the wind mass-loss rate by a factor of about four from its commonly used value. This strengthens an early conclusion, which was based on exoplanets with circular orbits, that states that to have a non-negligible fraction of AGB stars that engulf planets we should consider lower wind mass-loss rates of isolated AGB stars (before they are spun-up by a companion). Such an engulfed planet might lead to the shaping of the AGB mass-loss geometry to form an elliptical planetary nebula.

Comments: Will be submitted in two days to allow comments by readers

Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)

Cite as: arXiv:2004.09077 [astro-ph.SR] (or arXiv:2004.09077v1 [astro-ph.SR] for this version)

Submission history

From: Noam Soker 

[v1] Mon, 20 Apr 2020 06:12:59 UTC (1,570 KB)

https://arxiv.org/abs/2004.09077