My research currently revolves around all things Venus. We can expect to find a multitude of potentially Venus-like worlds in the coming years, and it is imperative that we deduce as much information from them as we can. Venus is incredibly similar to Earth in terms of mass, radius, and distance from the Sun. And it has been concluded that it could have maintained habitable conditions in its past. Determining what caused Venus' fall from grace is crucial for constraining the different evolutionary pathways of terrestrial planets, as well as determining which planets are habitable.
“Predicting the Yield of Potential Venus Analogs from TESS and their Potential for Atmospheric Characterization” C. Ostberg, S.R. Kane, (2019) Astronomical Journal
“Science Extraction from TESS Observations of Known Exoplanet Hosts”
S.R. Kane, Z. Li, E.T. Wolf, C.M. Ostberg, M.L. Hill, (2021), Astronomical Journal
“Venus has a locally thin lithosphere with active small upwellings and extension”
S.E. Smrekar, C.M. Ostberg, J.G. O’Rourke, (2021), Science (Submitted)
“A Global Survey of Lithospheric Flexure at Steep-Sided Domical Volcanoes on Venus Reveals
Intermediate Elastic Thicknesses”
M.E. Borelli, J.G. O’Rourke, S.E. Smrekar, C.M. Ostberg, (2021), JGR Planets
Constraining the Venus Zone boundaries
The Venus Zone (defined in Kane et al. 2014) is a 1st order estimate that determines the distance from a star where we can expect to find potential exo-Venus analogs. I plan to expand the definitions of the inner and outer boundaries so they can be applied to a variety of planetary masses and host-star stellar types. This will be accomplished using 3-D general circulation models (ROCKE-3D, VPLanet) and atmospheric loss models.
Plot from Ostberg & Kane (2019), showing estimated and discoverd TESS planets in reference to the Venus Zone
Generating spectra for Venus-like planets, and determining their observability
Ostberg & Kane (2019) predicts that the TESS mission will be discovering a multitude of potentially Venus-like planets. But how will we be able to confirm this prediction? With the help of JWST of course! I am working towards generating a diverse set of atmospheric spectra that can be used as a reference for future JWST observations. This can be done by assuming planetary atmospheric composition, or by generating plausible climate conditions using 3-D climate models and generating spectra from the results. I plan to do both to expedite the process of determining the nature of planets in the Venus Zone from retrieved transmission spectra.
A modelled transmission spectrum for a cloudless Venus
Determining the elastic thickness of the Venusian lithosphere
There is currently an assumption that Venus is currently in a stagnant-lid regime, which indicates that the planet is geologically dead. However studies have shown that Venus appears to have a thin elastic lithosphere on both regional (1000's of km) and local (100's of km) scales (Anderson & Smrekar 2006; O'Rourke & Smrekar 2018). Yet these studies have been discounted due to how much they deviate from current stagnant-lid models applied to Venus which assume very little heat flow. I am working to show that the results from these two studies, which use two entirely different techniques, agree. Agreement between these two studies points to the fact that Venus does in fact have a lithosphere with variable thickness, and will redefine how we model Venusian geology and heat flow.
Topographical profiles from Hepat corona on Venus which display lithospheric flexure