Making BEASTies: dynamical formation of planetary systems around massive stars

Abstract

Exoplanets display incredible diversity, from planetary system architectures around Sun-like stars that are very different to our Solar System, to planets orbiting post-main sequence stars or stellar remnants. Recently the B-star Exoplanet Abundance STudy (BEAST) reported the discovery of at least two super-Jovian planets orbiting massive stars in the Sco Cen OB association. Whilst such massive stars do have Keplerian discs, it is hard to envisage gas giant planets being able to form in such hostile environments. We use N-body simulations of star-forming regions to show that these systems can instead form from the capture of a free-floating planet, or the direct theft of a planet from one star to another, more massive star. We find that this occurs on average once in the first 10Myr of an association's evolution, and that the semimajor axes of the hitherto confirmed BEAST planets (290 and 556au) are more consistent with capture than theft. Our results lend further credence to the notion that planets on more distant (>100au) orbits may not be orbiting their parent star.

5 pages, 4 figures, published in MNRAS Letters

References in corpus (11)

• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• The nucleosynthesis of Al26 and Fe60 in solar metallicity stars extending in mass from 11 to 120 Msun: the hydrostatic and explosive contributions
• Kepler-62: A five-planet system with planets of 1.4 and 1.6 Earth radii in the Habitable Zone
• Cross Sections for Planetary Systems Interacting with Passing Stars and Binaries
• Not all stars form in clusters - measuring the kinematics of OB associations with $Gaia$
• The instability of planetary systems in binaries: how the Kozai mechanism leads to strong planet-planet interactions
• Rapid destruction of protoplanetary discs due to externalphotoevaporation in star-forming regions
• A wide-orbit giant planet in the high-mass b Centauri binary system
• The B-type Binaries Characterisation Programme I. Orbital solutions for the 30 Doradus population
• BEAST begins: Sample characteristics and survey performance of the B-star Exoplanet Abundance Study
• How do binary clusters form?

Cited by in corpus (2)

• Rotation Periods, Inclinations, and Obliquities of Cool Stars Hosting Directly Imaged Substellar Companions: Spin-Orbit Misalignments are Common
• Evaporation before disruption: comparing timescales for Jovian planets in star-forming regions