| Type |
Journal Article |
| Names |
Fabio Pacucci, Andrea Ferrara, Elena D'Onghia |
| Publication |
The Astrophysical Journal Letters |
| Volume |
778 |
| Pages |
L42 |
| Journal Abbreviation |
The Astrophysical Journal Letters |
| Date |
December 1, 2013 |
| DOI |
10.1088/2041-8205/778/2/L42 |
| ISSN |
0004-637X |
| URL |
http://adsabs.org/2013ApJ.778L.42P |
| Library Catalog |
labs.adsabs.harvard.edu |
| Abstract |
Recent observations have shown the presence of extra-solar planets in
Galactic open stellar clusters, such as in Praesepe (M44). These systems
provide a favorable environment for planetary formation due to the high
heavy-element content exhibited by the majority of their population. The
large stellar density, and corresponding high close-encounter event
rate, may induce strong perturbations of planetary orbits with large
semimajor axes. Here we present a set of N-body simulations implementing
a novel scheme to treat the tidal effects of external stellar perturbers
on planetary orbit eccentricity and inclination. By simulating five
nearby open clusters, we determine the rate of occurrence of bodies
extracted from their parent stellar system by quasi-impulsive tidal
interactions. We find that the specific free-floating planet production
rate \dot{N}_o (total number of free-floating planets per unit of time,
normalized by the total number of stars), is proportional to the stellar
density ρsstarf of the cluster: \dot{N}_o = \alpha \rho
_\star, with α = (23 ± 5) × 10–6
pc3 Myr–1. For the Pleiades (M45), we
predict that ~26% of stars should have lost their planets. This raises
the exciting possibility of directly observing these wandering planets
with the James Webb Space Telescope in the near-infrared band. Assuming
a surface temperature for the planet of ~500 K, a free-floating planet
of Jupiter size inside the Pleiades would have a specific flux of F
ν (4.4 μm) ≈4 × 102 nJy, which
would lead to a very clear detection (S/N ~ 100) in only one hour of
integration. |
| Tags |
open clusters and associations: general, stars: kinematics and dynamics |