SciPost Submission Page
Lucky planets: how circumbinary planets survive the supernova in one of the innerbinary components
by Fedde Fagginger Auer, Simon Portegies Zwart
Submission summary
As Contributors:  Simon Portegies Zwart 
Arxiv Link:  https://arxiv.org/abs/2101.08033v1 (pdf) 
Code repository:  http://amusecode.org 
Date submitted:  20210121 14:26 
Submitted by:  Portegies Zwart, Simon 
Submitted to:  SciPost Astronomy 
Academic field:  Astronomy 
Specialties: 

Approaches:  Theoretical, Computational 
Abstract
Since the discovery of exoplanets around pulsars, there has been a debate on their origin. Popular scenarios include in situ formation or the dynamical capture of a planet in a dense stellar system. The possibility of a planet surviving its host star's supernova is often neglected, because a planet in orbit around a single exploding star is not expected to survive the supernova. A circumbinary planet, however, may stand a chance in staying bound when one of the binary components explodes. We investigate the latter and constrain the distribution of postsupernova orbital parameters of circumbinary planets. This is done by performing population synthesis calculations of binary stars until the first supernova. Just before the supernova, we add a planet in orbit around the binary to study its survivability. In our supernova model, the exploding star's mass is assumed to change instantaneously, and we apply a velocity kick to the newly formed remnant. The mass loss and velocity kick affect the orbits of the two stars and the planet. Only $2 \cdot 10^{3}$ of systems survive the supernova while keeping the circumbinary planet bound. The surviving planetary orbits are wide ($a \apgt 10$ au) and eccentric ($e \apgt 0.3$). It turns out much more likely ($3\cdot 10^{2}$ system fraction) that the newly formed compact object is ejected from the system, leaving the planet bound to its companion star in a highly eccentric orbit (typically $\apgt 0.9$). We expect that the Milky way Galaxy hosts at most $10$ xray binaries that are still orbited by a planet, and $\aplt 150$ planets that survived in orbit around the compact object's companion. These numbers should be convolved with the fraction of massive binaries that is orbited by a planet.