About Event

Wed 22 Feb 2023


This colloquium is hosted by STScI and will be held as an in-person event.


3:00 PM - 4:00 PM EST

Contact Information

Have questions? Please contact STScI.


Thermally-pulsing Asymptotic Giant Branch (TP-AGB) stars dominate the IR flux in star-forming galaxies (up to 70%). This dominance has a significant impact on model-dependent derived galaxy properties like the star-formation rate and stellar mass, yet the stellar models that yield these results are not able to reproduce TP-AGB observed properties. HST's medium-band IR filters are uniquely suited for TP-AGB observations and have enabled the first TP-AGB calibration observations in galaxies beyond the Milky Way system. This capability significantly broadens the metallicity and age baselines for model calibrations, making them far more broadly applicable than what has been provided by the typically-used Magellanic Clouds. I will present new results using these HST filters to identify TP-AGB stars in M31 and other nearby galaxies and discuss similar strategies with JWST, as revealed by the Stellar Populations ERS program. I will also discuss complementary work done with Spitzer to quantify the TP-AGB dust production and mass loss and upcoming JWST programs. Combined, HST, JWST, and future facilities such as Roman and LSST will lead to improvements in modeling that will finally solve the many long-standing TP-AGB star problems that have plagued extragalactic astronomy.

Speaker: Martha Boyer (STScI)


All 2023 Spring Colloquium talks are held on Wednesdays at 3:00 PM.  You may join the colloquium in person at STScI’s John N. Bahcall Auditorium or virtually or at the links listed below. 

Please direct questions or comments to contact above. The Spring Colloquium Committee members are: JHU Members: Kevin Schlaufman, Co-Chair, Ethan Vishniac, Arshia Jacob and STScI Members: Joel Green, Co-chair, Armin Rest, Co-chair and Andreea Petric.