The lowest-mass stars and substellar objects serve as a natural bridge between stars and planets, covering the peak of the initial mass function and representing the most common outcomes of star formation in the universe. Investigating their disks and atmospheres provides useful insights into the potential connections and distinctions between star and planet formation mechanisms. In this talk, I will focus on two key substellar properties: the nature of circumsubstellar disks at young ages, and the atmospheric properties of brown dwarfs at advanced ages. Observational studies spanning the UV to the sub-mm are now enabling the first in-depth examinations of gas, dust, and accretion indicators for systems across the stellar/substellar boundary, including those with potentially 'giant planet-forming' transitional disks, and we are now able to extend such multiwavelength studies to the disks of widely-separated planetary-mass companions. The sensitivity and wavelength grasp now achievable across the NIR/MIR with JWST are opening up new avenues for circumplanetary disk detection and characterization, while simultaneously allowing us to obtain the most detailed views yet into the atmospheric chemistry of cool substellar objects.

Speaker: Kimberly Ward-Duong (Smith College) 

The 2025 Spring Colloquium talks are held on Wednesdays at 3:00 PM. This colloquium is hosted by STScI and will be held as an in-person and virtual event.

You may join in person at STScI’s John N. Bahcall Auditorium or virtually on STScI's Live Science Events Facebook page.

Please direct questions or comments to contact above. The 2025 Spring Colloquium Committee members are: Nestor Espinoza (STScI), Joel Green (STScI), Nick Indriolo (STScI), Elena Manjavacas (STScI), Namrata Roy (JHU), Kevin Schlaufman (JHU), Ethan Vishniac (JHU).