Astronomy Colloquium for 2023-11-29

Series: Astronomy Colloquium
Date: Wednesday 29-Nov-2023
Time: 16:05-17:00 (4:05-5:00 pm)
Location: ATL 2400
Speaker: Dr. Michael Kelley (University of Maryland)
Title: JWST reveals water ice in the asteroid belt

Nearly 30 years ago, comet 133P/Elst-Pizarro was discovered in the asteroid belt. Despite having a stable orbit seemingly no different from any other outer main belt asteroid, this object had a tail. Three months and several telegrams later, the cometary nature was confirmed based on a morphology that was best described by continuous mass loss over a period of weeks to months. Fast forward to today, and a variety of mass-loss mechanisms have been identified in asteroid belt members, including impacts and rotational instability. But only the so-called "main-belt comets" like Elst-Pizarro repeatedly produce dust near perihelion, suggesting activity driven by water ice sublimation. These objects present the exciting possibility that outer belt asteroids can preserve water ice in their interiors over the ~4.5 Gyr lifetime of the Solar System. However, 15 years of attempts to detect gas around main-belt comets have only returned upper-limits. That is, until JWST observed comet 238P/Read in 2022. I will review the JWST observations of comet Read and the findings based on them, and share a few other cometary results from the first year of JWST's science operations.

In-person colloquia are usually preceded by espresso and ice cream at 1:45 pm outside room PSC 1150 and are followed by an informal reception at 5:15 pm in that room. Anyone interested in talking with the speaker, or being added to the colloquium announcement email list, should contact the colloquium organizer Dr. Leslie Sage. Lunch will normally be reserved for the speaker to talk to graduate students. Anyone asking a question during a talk is asked to raise their hand and be acknowledged before speaking. Contact Dr. Leslie Sage for details.

Colloquium Organizer: Dr. Leslie Sage


Special accommodations for individuals with disabilities can be made by calling (301) 405-3001. It would be appreciated if we are notified at least one week in advance.


Directions and information about parking can be found here.

This page was automatically generated on: 09-Nov-2023.