2018 Sagan Exoplanet Summer Workshop

Did I Really Just Find an Exoplanet?

Hands On Session Information

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Thank you to our hands-on session developers and helpers!

  • VESPA: Tim Morton (Princeton/Univ. of Florida), Andrew Vandeburg (UT Austin), Juliette Becker (Univ. of Michigan), Ashley Baker (Univ. of Pennsylvania)
  • EXOFASTv2: Jason Eastman (Harvard-Smithsonian CfA), Joey Rodriguez (Harvard-Smithsonian CfA), Jonathan Jackson (Penn State University), Tobias Hinse (KASI-Korea), Julian van Eyken (Caltech/IPAC-NExScI)

  • Hardware and Software Requirements:

    You will need your computer and, if available, an ethernet port or adapter to connect to an ethernet cable. One of the rooms here the hands-on sessions will be held offers both wired and wireless internet connections, while the other room has only wireless connections. We strongly suggest you use the wired connection in the room where it is available.

    The software for the hands-on sessions will be installed on the Amazon cloud (Amazon Web Services, or AWS). To log in to your AWS account (log in information will be provided when you pick up your badge) and then run the software, you will need an X terminal and X server. On macOS, the Terminal app is already included as your terminal emulator. You may also have to install XQuartz ( On Windows operating systems, you will need to install a software package such as Cygwin ( to get a terminal emulator and X server.

    Background information on Linux, xterm, unix with useful commands for the hands-on sessions (click to view)


    The hands-on sessions will be introduced on the first day of the workshop, including short presentations on the software - EXOFASTv2 and VESPA - that will be used on Tuesday and Wednesday. Workshop attendees will then be asked to sign-up for a group project using one of these software packages. You will need your laptop for the hands-on sessions.

  • Monday's hands-on session will introduce participants to the TESS mission and engage them in group discussions about TESS validation and follow-up. No software will be used for this hands-on session.
  • Discussion Prompts for the Monday hands-on session (click to view)

  • For Tuesday's hands-on session, participants will split into two groups; one will use VESPA for statistical validation of transiting planets, and one will use EXOFASTv2 to fit transit photometry and radial velocity data to derive exoplanet properties. There will be time at the end of this session to start working on your group projects.

    • If you signed up for an EXOFASTv2 project, you will do the EXOFASTv2 hands on session on Tuesday (and VESPA on Wednesday).
    • If you signed up for a VESPA project, you will do the VESPA hands on session on Tuesday (and EXOFAST on Wednesday).
  • Wednesday is a repeat of Tuesday, with the two groups switching places, so all participants will have a chance to learn both VESPA and EXOFASTv2.
  • On Thursday participants will work on group projects and prepare their presentations, which will be shown on Friday afternoon at the conclusion of the workshop.

    The software will be installed on the Amazon cloud, so there is no need for participants to install it on their laptops (but they are welcome to do so if they want to try it out; however, we cannot provide any support).

    EXOFASTv2 Software:

    This software package, written in IDL by Jason Eastman, will be used to fit transit photometry and radial velocity data to derive exoplanet properties. EXOFASTv2 has been an important fitting tool for astronomers who want to use transit light curves or radial velocity data and various inputs to create models of planet systems. Planet and stellar properties are derived self-consistently, and MCMC is used to characterize the uncertainties.

  • Main paper: EXOFAST: A Fast Exoplanetary Fitting Suite in IDL
  • Github link:
  • EXOFASTv2 Hands-On Session (click to view)
  • EXOFAST on the NASA Exoplanet Archive

    The NASA Exoplanet Archive has integrated Jason Eastman's EXOFAST code into its suite of web services, which provides the tool with a more robust and stable home with several enhancements.

    The Exoplanet Archive's version of EXOFAST offers the same IDL-based calculations as the original code, and also provides sufficient back-end computing resources to enable Markov Chain Monte Carlo (MCMC) analysis. In addition, the new EXOFAST draws on the archive's database of stellar and planetary parameters, which are updated weekly based on the current literature.

    VESPA Software:

    This software package, written in Python by Tim Morton, calculates the false positive probabilities for transit signals and statistically validates transiting exoplanets. It uses information from the light curve, and, if available, results from follow-up spectroscopy and imaging data.

  • Main paper: An Efficient Automated Validation Procedure for Exoplanet Transit Candidates
  • Github link:
  • VESPA Tutorial (click to view)
  • VESPA Workshop Projects (click to view)

  • Questions?

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    (last updated July 26th, 2018 08:11:29)