Sarah Betti

My dissertation research focuses on studying the gas and dust in circumstellar disks around young accreting brown dwarfs and low mass stars. The mechanisms for magnetospheric accretion, where infalling inner disk material flows along stellar magnetic field lines and forms a shock in a star’s atmosphere, is well-established for young T Tauri stars and has long been thought to be the same mechanism which governs how the lowest mass stars and planetary mass companions form and gain mass. However, high accretion rates measured from known protoplanets candidates challenge our understanding of the physical mechanisms that control accretion in these lowest mass objects. By studying how this gas and dust accretes onto the lowest mass stars and planetary mass companions through a variety of multiwavelength accretion tracers (including Balmer, Paschen, Brackett Hydrogen lines along with UV continuum excess), we will be able to determine the physical accretion mechanisms for low mass stars and planets and inform our understanding of planet formation within these disks. Along with studying accretion in young stars, I am also looking at the distribution of icy grains within circumstellar disks. The size and distribution of these icy grains will inform our theories of giant planet formation and planet filtration models.