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Advances in Astronomy
Volume 2012 (2012), Article ID 697967, 8 pages
Research Article

Transit Analysis Package: An IDL Graphical User Interface for Exoplanet Transit Photometry

1Institute for Astronomy, University of Hawaii, 2680 Woodlawn Dr, Honolulu, HI 96822, USA
2Department of Astrophysics, California Institute of Technology, MC 249-17, Pasadena, CA 91125, USA
3NASA Exoplanet Science Institute (NExScI), CIT Mail Code 100-22, 770 South Wilson Avenue, Pasadena, CA 94720, USA
4Department of Physics & Astronomy, The University of British Columbia, Vancouver, BC, V6T1Z1, Canada
5The Ohio State University, Columbus, OH 43210, USA
6Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA

Received 26 September 2011; Accepted 19 February 2012

Academic Editor: Cesare Barbieri

Copyright © 2012 J. Zachary Gazak et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We present an IDL graphical user-interface-driven software package designed for the analysis of exoplanet transit light curves. The Transit Analysis Package (TAP) software uses Markov Chain Monte Carlo (MCMC) techniques to fit light curves using the analytic model of Mandal and Agol (2002). The package incorporates a wavelet-based likelihood function developed by Carter and Winn (2009), which allows the MCMC to assess parameter uncertainties more robustly than classic χ2 methods by parameterizing uncorrelated “white” and correlated “red” noise. The software is able to simultaneously analyze multiple transits observed in different conditions (instrument, filter, weather, etc.). The graphical interface allows for the simple execution and interpretation of Bayesian MCMC analysis tailored to a user’s specific data set and has been thoroughly tested on ground-based and Kepler photometry. This paper describes the software release and provides applications to new and existing data. Reanalysis of ground-based observations of TrES-1b, WASP-4b, and WASP-10b (Winn et al., 2007, 2009; Johnson et al., 2009; resp.) and space-based Kepler 4b–8b (Kipping and Bakos 2010) show good agreement between TAP and those publications. We also present new multi-filter light curves of WASP-10b and we find excellent agreement with previously published values for a smaller radius.