Brown dwarfs and rogue planets in star forming regions

What is the lowest mass object that can form like a star? And how many massive planets are ejected from their planetary systems during the formation process? These two questions will be tackled in this project.

Over the last years, we have carried out a search for the lowest mass free-floating objects in star forming regions, in a project called SONYC (short for Substellar Objects in Nearby Young Clusters). In SONYC we used the largest existing ground-based telescopes to make ultradeep surveys of the youngest clusters on the sky. While we found plenty of brown dwarfs (with some interesting evidence for environmental difference in the formation of brown dwarfs), we did not find many objects with super-Jupiter masses, the presumed ejected giant planets. If they exist (and we expect that they do), they will be below our mass threshold of 5 Jupiter masses and are still to be discovered.

In the next step of this project (and in this PhD project) we will use the James Webb Space Telescope to explore the domain of free-floating rogue planets with masses between 1 and 5 Jupiter masses. We have good chances to get observing time to get this project started right after the JWST begins operation in 2018. The student will prepare the observations and explore follow-up avenues, with JWST and other facilities, and then be the first to analyse the data. In addition, we will work with the second data release from Gaia to pin down the fundamental parameters of young brown dwarfs. This will lead to new contraints on star formation simulations and insights into the transition from star to planet formation.

This will be a strongly observational project, which requires to learn the details of optical and infrared observations, the physics of ultracool objects, the intricacies of disentangling emission from objects, disks, and accretion, as well as an interest in collaborating with people from the theory side, including atmospheric physics and star/planet formation.