Amy Steele

MSI Postdoctoral Fellow
McGill Space Institute (MSI)
asteele 'at' physics 'dot' mcgill 'dot' ca

Amy in a hat

Circumstellar Material on and off the Main Sequence

I study gas and dust around stars like the sun and much older.
Debris disks around main sequence stars, dust formation from planet engulfment by giant stars,
stellar mass loss by super giant stars, and the tidal disruption of exoplanetary material by white dwarfs,
all inform our knowledge of the composition of the remnants of stellar formation.

Debris Disks

Debris disks around main sequence stars are generated through the collisions of planetesimals that are remnants of stellar evolution. Spatially resolved observations are crucial to characterize the structure of the dust disk and break degeneracies inherent in SED modeling. Using submillimeter wavelength observations I show that gas-poor debris disks around solar analogues generally exhibit properties consistent with scaled-up versions of the Solar System's Kuiper Belt.

Resolved mm-wavelength observations of debris disks

Dust around giants is also very cool. Check out my poster below!

White Dwarfs with Disintegrating Planet(esimal)s

If an exo-asteroid or exo-planet were to get too close to a compact object like a white dwarf, the remnant of evolution for ~95% of stars, it could be ripped apart due to tidal forces. If the geometry is just right, we might see the distrupted pieces transit the white dwarf. This is the case for a number of systems, most notable WD 1145+017.


White Dwarfs as Mass Spectrometers

If a WD is in the process of ripping apart an exoplanetary body, light that interacts with the resulting gas would reveal the chemical composition of the disrupted body through an absorption and/or emission spectrum (WD spectra typically contain only H or He absorption lines that are gravitationally redshifted). Features from elements heavier than H or He (i.e., metals) in WD spectra are thought to originate from planetary system material. The existence of WDs with metals in their photospheres and evidence of circumstellar gas tied to the tidal disruption of a planetesimal, has provided a new method to determine the composition of extrasolar planetary bodies.

A Characterization of the Circumstellar Gas around WD 1124-293 using Cloudy




I am a big fan of observing! I want all of the data all the time. Light is awesome.

Service with GRAD-MAP

Graduate Resources Advancing Diversity with Maryland Astronomy and Physics (GRAD-MAP) is a diversity
initiative at the University of Maryland in the Astronomy and Physics departments.
I was the team lead of this program for two years and served as an advisor for one year.
There are three main parts to the program: fall outreach/collaboration, a Winter Workshop, and a Summer Research Experience.

More Service

Astronomy Graduate Council

Served on the council for 5 years

Astronomy Graduate Admission

Participated in interviews of potential graduate students for 2 years

Astronomy Chair Search

Graduate representative on the committee to elect a new department chair.

Astronomy Social Events Coordinator

Organized events for the astronomy graduate students to help improve comradery and morale.

Astronomy Graduate Student Deputy

A department position akin to a graduate student vice president.

UMD Graduate School Centennial Panelist

Selected to participate in a panel discussion about service as a graduate student.