Laura Kreidberg

I am a National Science Foundation Graduate Research Fellow in the Department of Astronomy and Astrophysics at the University of Chicago, where I work with Jacob Bean on characterizing the atmospheres of extrasolar planets.

Recent Results

A solar abundance of water for the hot Jupiter WASP-43b

We used HST/WFC3 to obtain ultra-precise transmission and emission spectra for WASP-43b, one of the shortest-period hot Jupiters. These data reveal that the water abundance in the planet's atmosphere is consistent with expectations for a solar composition gas to within one order of magnitude. This is a more precise measurement of the water content than is available for the solar system giant planets, which have water locked up in icy clouds that are out of reach of remote observations. In addition, we also observed three full-orbit, spectroscopic phase curves of the planet and used these to map the thermal structure of the atmosphere as a function of longitude and altitude.

These results are published in two companion papers, available here (water abundance) and here (thermal structure). A general summary is available in the Space Telescope press release, or articles at space.com and National Geographic. I also made a YouTube video illustrating what we learned and how we learned it - see here.

Kreidberg et al. 2014, ApJ, 793L, 27
Kreidberg et al. 2014, Nature 505, 69
Clouds in the atmosphere of the super-Earth GJ 1214b

We observed a record 15 transits of GJ1214b with HST/WFC3 to measure the planet's transmission spectrum to unprecedented precision. This is the first measurement sensitive to an Earth-like atmospheric composition on an exoplanet, though that is not what we found! The featureless spectrum we obtained conclusively rules out all plausible cloud-free, high mean molecular mass compositions. The best explanation for the data is that high altitude clouds must be present in the atmosphere. For more info, see our paper, or some of the associated media coverage at NASA, Nature, NPR, Time Magazine, the NYT, or space.com.

I also made a video with an introduction to our findings for non-scientists; check it out on YouTube!

C.V.

Education

University of Chicago, Ph.D. Astronomy and Astrophysics; expected graduation 2016
Yale University, B.S. Astronomy and Physics, 2011, with distinction

Awards and Honors

NSF Graduate Student Research Fellowship, 2013-2016
Illinois Space Grant Consortium Fellowship, 2012-2013
George Beckwith Prize for excellence in astronomy, Yale University, 2011

Publications

Code

See the tar file below for a fast transit light curve code written in Python, with heavy lifting done by C extensions.  The code uses a quadratic limb darkening law and is based on the original Fortran version provided by Mandel & Agol (2002).  It provides more than an order of magnitude speed-up over a pure Python version.  The directory contains a README file with instructions on compilation and an example code, demo.py. If you use the code, please send me your contact information so I can alert you to bug fixes or other improvements.

fastM&A.tar

Updates
8/21/14:
Correction to handle the corner case (z,p) = (0.5, 0.5). Thanks to Ethan Kruse for catching it!
9/8/14:
Bug fix for eccentric anomaly calculation. Thanks Geert Jan Talens!

Contact

laura (dot) kreidberg (at) uchicago (dot) edu