The Formation of Giant Planets on Wide Orbits

University Of Texas At Austin, Austin TX

Investigators

Abstract

This work will focus on understanding how large planets form in the outer reaches of a solar system. Planet formation in the inner regions of a solar system is reasonably well understood. Further out - up to thousands of AU away from a parent star - there is no established model to explain recent startling discoveries of massive planets in these areas. The researchers will analyze recently-gathered survey data from the Keck Observatory to establish if and how the number and mass of planets in the outer reaches of a solar system depends on the mass of the parent star. The form of this dependence (or its lack) might shed light on the new Disk Instability model as a potential formation mechanism. The survey data represent 400 young, low-mass red dwarf stars, and comprises the largest survey in this stellar mass range. The team will include a graduate student, as well as three undergraduate summer students. These students will participate through UT's TAURUS program, which makes research opportunities in Astronomy available to under-represented students. The team will analyze Keck NIRC2 coronagraph data of 400 young, low-mass stars to directly image planetary companions in far orbits. The survey data incorporate previously unknown young K- and M- dwarfs that the team identified using a new methodology to locate members of nearby young moving groups. There are three phases involved in this work: (1) the team will establish the ages and kinematic group membership of the sample using high-resolution spectroscopy combined with new parallaxes from Gaia DR2; (2) the team will carry out PSF subtraction for all coronagraphic observations using a large reference library they will compile comprising thousands of NIRC2 PSF templates; and (3) they will measure the relationship between giant planet frequency and stellar host mass through a meta-analysis of the program together with published surveys in the literature. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.