Multiwavelength Observations of Disintegrating Transiting Planets & Planetesimals

Bryce Croll

Institute for Astrophysical Research, Boston University

Recently there have been a number of low-mass planets and planetesimals announced (or soon to be announced) transiting low-mass stars and even a white dwarf - intriguingly, these planets are believed to be disintegrating with long cometary tails trailing behind them. The evidence that these bodies are disintegrating are: (i) that they usually display longer transit egresses than ingresses, likely indicative of a trailing cometary tail, and (ii) they they display variable transit depths, likely indicative of light scattering from a variable amount of material in the cometary tail that has disintegrated from the planet. I'll present multiwavelength photometry that allows us to place limits on the particle sizes in the cometary tails trailing these planets, and therefore helps to determine the mechanism causing these planets to disintegrate. I'll finish with an in-depth discussion of the up to six or more disintegrating planetesimals in short periods (<5 hour) orbits that are shortly to be announced orbiting a single white dwarf - I will explain how the multiwavelength photometry that we've obtained helps to answer how many planetesimals are actually orbiting this white dwarf, whether the orbits of these objects are stable, and what the most likely mechanism is (tidal disruption, collisions, a Parker-wind, etc.) that has led to both these planetesimals' cometary tails and the arrival of these bodies in such short period orbits.

Date: Jeudi, le 15 octobre 2015
Heure: 11:30
Lieu: Université de Montréal
  Pavillon Roger-Gaudry, local D-460
Contact: Patrick Dufour