Carl A. Schmidt

Planetary Science

schmidtc @
Curriculum Vitae
PhD Thesis
Recent Talks


I'm a research scientist at the Boston University Center for Space Physics studying tenuous planetary atmospheres, also known as exospheres. Prior, I was a post-doc at CNRS/LATMOS, where I maintain a joint appointment, and a post-doc at University of Virginia. This site contains scattered bits of information about my various projects.


Atmospheres of the bodies below are now being studied using a new instrument built here at Boston University called the Rapid Imaging Planetary Spectroagraph (RIPS). RIPS is a visiting instrument, splitting its time between the AEOS 3.7m at Haleakala and the Perkins 1.8m telescope at Lowell Observatory. More about RIPS


Mercury's atmospheric content is comparable to the amount of air in a small building, spread over the whole planet. Still, its bright sodium and potassium D emission lines are easily observable by small ground-based telescopes. Interpreting such observations and connecting them to the extensive MESSENGER dataset is a job for numerical models. Several of my projects involve observing Mercury's thin atmosphere and developing simulations of various ground- and space-based measurements. More on Mercury


Cometary atmospheres are rich in complexity. Using an integral field spectrograph, I've studied the composition, structure, and dynamics of Comet C/2012 S1 (ISON), which, well. . . fell into the Sun. Then I worked with the STEREO spacecraft to study striae formation in Comet C/2011 L4 (Pan-STARRS). I then chased 46P/Wirtanen when it passed near Earth in December 2018, but it was fainter than expected. Now I'm impatient with faint comets and awaiting on another bright one to fly in from the Oort cloud.


Jupiter's volcanic moon Io is certainly one of the most interesting object's in our Solar System. I use various telescopes to observe its atmospheric changes and escape, and a spectrograph at Apache Point Observatory to track a wobbly doughnut orbiting Jupiter called the Io Plasma Torus. Recent work revolves around coordinated datasets using RIPS, Hubble's Cosmic Orgins Spectrograph and Apache Point. I also lead some ground-based telescope efforts for Juno mission support related to Io studies.


Io can potenitally transfer some of its massively extended atmosphere to an adjacent moon, Europa. I'm currently working on a better understanding of the fraction of the sodium in Europa's atmosphere that is transferred from Io, rather than of native origins. Addressing this question ultimately helps solve another: what is the salinity of Europa's subsurface ocean?


Earth's moon has a sodium atmosphere similar to Mercury's. During the LCROSS impact, colleagues at McDonald Observatory recorded a time series of a plume of sodium extending some 200 km above the impact site. RIPS also took some interesting data of the lunar atmosphere during its comissioning at Lowell Observatory that our research group is modelling now. The Moon's escaping atmosphere has a cool interaction with the Earth around New Moon--that's a long story (pun intended) so here's more about the Moon's atmosphere