Maria Steinrueck

I am a fourth-year graduate student at the Lunar and Planetary Laboratory at the University of Arizona.

Research

My research focuses on studying the atmospheres of exoplanets with three-dimensional numerical simulations (so-called General Circulation Models or GCMs). I concentrate on close-in gas giants, such as hot Jupiters, warm Neptunes and mini Neptunes. These planets are tidally locked, meaning that one side of the planet permanently faces the star. This creates strong day-night temperature contrasts which drive a fascinating atmospheric circulation dominated by an eastward equatorial jet. I am interested in examining how this circulation shapes chemical processes, such as disequilibrium chemistry, cloud or haze formation, as well as in how these processes in turn influence the atmospheric circulation and radiative transfer.

HD189733b

Image: NASA/ESA/STScI (G. Bacon)

Temperature difference at the 30 mbar level

Temperature difference compared to equilibrium chemistry at the 30 mbar level in a simulation with a CH4/CO abundance ratio of 0.01. For more information, see Fig. 4 in Steinrueck et al. (2019).

Disequilibrium chemistry on Hot Jupiters

The strong winds on hot Jupiters impact the abundances of methane and carbon monoxide, two important absorbers of infrared radiation. Neglecting the atmospheric circulation, one would expect to find carbon monoxide on the day side and methane on the night side. This assumption (called equilibrium chemistry) has been used in many models, including most 3D simulations of hot Jupiter atmospheres with realistic radiative transfer. Taking into account the strong winds, however, the methane and carbon monoxide abundances are homogenized between day and night side, as the winds transport gases faster than chemical reactions can take place. It has been hypothesized that including this effect in 3D simulations could explain the discrepancy between observed and simulated light curves of hot Jupiters. I included this effect of disequilibrium chemistry in a 3D simulation of a hot Jupiter. I found that including disequilibrium chemistry leads to significant temperature changes (larger than 50-100 K) in simulations of hot Jupiter HD 189733b. If CO is the dominant carbon species in chemical disequilibrium, the day side cools and the night side heats up. In the less likely CH4 dominated regime, the atmosphere becomes hotter than in the equilibrium chemistry case everywhere on the planet for pressures larger than 30 mbar. Looking at observations predicted from our model, I showed that disequilibrium chemistry cannot explain the observed discrepancies. In fact, while there is little effect on the light curve in the Spitzer 4.5 micron band, the day-night contrast in the 3.6 micron band becomes much smaller when including disequilibrium chemistry—the opposite of what is needed to match observations! I conclude that other effects not included in our model, most likely night side clouds, must be responsible for these discrepancies.

Read full journal article

CV

You can find a PDF of my CV here.

Contact

msteinru (at) lpl (dot) arizona (dot) edu

Lunar and Planetary Laboratory
Kuiper Space Sciences Bldg, Office #334
1629 E. University Blvd.
Tucson, AZ 85721

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