Evaporation before disruption: comparing timescales for Jovian planets in star-forming regions

Abstract

Simulations show that the orbits of planets are readily disrupted in dense star-forming regions; planets can be exchanged between stars, become free-floating and then be captured by other stars. However, dense star-forming regions also tend to be populous, containing massive stars that emit photoionising radiation, which can evaporate the gas in protoplanetary discs. We analyse N-body simulations of star-forming regions containing Jovian-mass planets and determine the times when their orbits are altered, when they become free-floating, and when they are stolen or captured. Simultaneously, we perform calculations of the evolution of protoplanetary discs when exposed to FUV radiation fields from massive stars in the same star-forming regions. In almost half (44 per cent) of the planetary systems that are disrupted - either altered, captured, stolen or become free-floating, we find that the radius of the protoplanetary disc evolves inwards, or the gas in the disc is completely evaporated, before the planets' orbits are disrupted. This implies that planets that are disrupted in dense, populous star-forming regions are more likely to be super Earths or mini Neptunes, as Jovian mass planets would not be able to form due to mass loss from photoevaporation. Furthermore, the recent discoveries of distant Jovian mass planets around tightly-packed terrestrial planets argue against their formation in populous star-forming regions, as photoevaporation would preclude gas giant planet formation at distances of more than a few au.

8 pages, 6 figures, accepted for publication in MNRAS

References in corpus (17)

• Four annular structures in a protostellar disk less than 500,000 years old
• UV Radiation Fields Produced by Young Embedded Star Clusters
• The evolution of dust in discs influenced by external photoevaporation
• Protoplanetary disc evolution affected by star-disc interactions in young stellar clusters
• A case of simultaneous star and planet formation
• Cluster dynamics largely shapes protoplanetary disc sizes
• The first multi-dimensional view of mass loss from externally FUV irradiated protoplanetary discs
• 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
• Perturbation of Compact Planetary Systems by Distant Giant Planets
• Long-Period Giant Companions to Three Compact, Multiplanet Systems
• The growth and migration of massive planets under the influence of external photoevaporation
• Dynamical evolution of star-forming regions: III. Unbound stars and predictions for Gaia
• Kepler-167e as a Probe of the Formation Histories of Cold Giants with Inner Super-Earths
• Far and extreme ultraviolet radiation fields and consequent disc destruction in star-forming regions
• Constraining the initial conditions of NGC 2264 using ejected stars found in Gaia DR2
• Making BEASTies: dynamical formation of planetary systems around massive stars