2017 Sagan Exoplanet Summer Workshop

Hands On Sessions

August 7-11, 2017
Hosted by The NASA Exoplanet Science Institute

back to 2017 Workshop home page

During the hands-on session, we will show how to identify and model microlensing planets in WFIRST-like data. First, we will identify planetary signals in both previously published microlensing events and simulated WFIRST light curves. Then, we will estimate the parameters of those planets using analytic methods. Finally, we will perform full numerical fits to the simulated WFIRST data to study the kinds of planets that WFIRST will find through microlensing.

Hands On Session Exercises

In this group activity, students learn to identify and analyzed planetary anomalies in microlensing light curves. It is designed for 8 groups of 4-10 people each, a minimum of 4 people per group is recommended (reduce the total number of groups if necessary).

Each group gets a packet of light curves for which they will identify and characterize the planets. There are 8 packets (numbered 0 -- 7) in addition to the training sets. Each packet will contain a specific type of planet (i.e. a specific range of s and q). The goal is that each group will gain familiarity with planetary perturbations arising from a particular type of planet. Then, through the presentations, they can get a sense of how planet perturbations change with the planet parameters.

The specific activities are to:

  1. As a group, sort the light curves into point lenses, probable planets, and other.
  2. Each group member selects a planetary light curve to solve.
    • Use Gaudi & Gould to qualitatively determine the planet parameters.
    • Fit that light curve using the qualitative parameters as a starting point.
  3. For the presentation, each group should
    • present the light curves fitted with both the qualitative and quantitative planet parameters with an arrow pointing to the planetary perturbation.
    • show the distribution of planet parameters in s, q space (perhaps plot both qualitative and quantitative)
    • relate those parameters to physical parameters assuming a M dwarf and G dwarf host

As a wrap-up, show the distribution of planets given to each group on the same plot.

Guide to the Files

All files listed under "Training Set from the Literature" and "Simulated WFIRST Microlensing Data" can be downloaded individually below, or all together in this TAR file.

Training Set from the Literature
  • LCExamples.pdf: example light curves from the literature with explanations about the observed planetary perturbations.
    • 01Packet.pdf: 20 light curves taken from the literature including point lenses, planets, and binary (star) microlenses.
      • 02Bonus.pdf: 10 additional light curves taken from the literature including point lenses, planets, and binary (star) microlenses. These include more pathological cases including resonant caustic planets and planets in binary star systems.
        • GroupEventClassifications.xlsx: A spreadsheet for each team to record their answers.
          • key.pdf: Answer key for LCExamples.pdf, 01Packet.pdf, and 02Bonuses.pdf. Gives light curve type, (s,q) if relevant, and citation from the literature.

          • Simulated WFIRST Microlensing Data

            For each group (0-7), there is a packet of simulated, WFIRST-like data. In the following list, [X] may be replaced by a number from [0, 7].

            • all_events_[X].pdf
            • Plots of 25 light curves showing both the full light curve (covering 3 WFIRST seasons), and just the season with the peak of the light curve (which includes any perturbations). These light curves consist of 10 point lenses, 10 planets, and 5 binary (star) lenses.

              all_events_0.pdf | all_events_1.pdf | all_events_2.pdf | all_events_3.pdf | all_events_4.pdf | all_events_5.pdf | all_events_6.pdf | all_events_7.pdf

              • planets_[X].pdf
              • Plots zoomed in on the planetary perturbations from all_events_[X].pdf

                planets_0.pdf | planets_1.pdf | planets_2.pdf | planets_3.pdf | planets_4.pdf | planets_5.pdf | planets_6.pdf | planets_7.pdf

                • gl_planets_[X].txt
                • A list of the planets in all_events_[X].txt including the mapping between their event designations and the data file names.

                  gl_planets_0.txt | gl_planets_1.txt | gl_planets_2.txt | gl_planets_3.txt | gl_planets_4.txt | gl_planets_5.txt | gl_planets_6.txt | gl_planets_7.txt

                  • master_[X].txt
                  • Answer key for all light curves in all_events_[X].pdf. Includes the full, true set of microlensing parameters used to generate the light curve as well as the mapping between the event designation and the data file names.

                    master_0.txt | master_1.txt | master_2.txt | master_3.txt | master_4.txt | master_5.txt | master_6.txt | master_7.txt

                    • WFIRST_SAGAN_[X]/
                    • Zip files containing the data files (date, mag, err) for the light curves shown in all_events_[X].pdf. Also includes data files for other types of simulated events, e.g. additional binaries, high-magnification planets (HMPlanet), and planets without caustic crossings (NCPlanet).

                      These files contain:

                      • Parameters_[X].txt A list of the micorlensing parameters used to generate each data file.
                      • WFIRST_####.dat A light curve data file.

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                      Other Files, Including Talks
                      • HandsOn_Introduction.pptx Brief overview of the goals of the HandsOn Sessions.
                      • Monday_HandsOn_LCExamples_Yee.pptx Powerpoint version of LCExamples.pdf.
                      • Tuesday_HandsOn_Yee.pptx Guide to analytically calculating the microlensing parameters from a light curve.
                      • Worksheet.docx Worksheet for calculating the microlensing parameters from a light curve. To be used with Tuesday_HandsOn-Yee.pptx.
                      • Wednesday_Hands_On.pdf Detailed documentation to accompany the pyLIMA notebook for numerically fitting the microlensing parameters.
                      • HandsOn_Thursday_Presentation_Prep.pdf Instructions for preparing the presentations with specific questions that should be addressed.

                      • Additional Microlensing Resources

                        Conceptual Themes for the 2017 Sagan Summer Workshop

                        Microlensing Source is a resource center for all aspects of gravitational microlensing. It aims to make microlensing more accessible for anyone with an interest in the subject, including students considering a career in the field, citizen scientists and those looking for a ready reference.

                        An introduction to microlensing tutorial was held at Caltech prior to the 21st International Microlensing Conference in February 2017. The tutorial included the following presentations:

                        • Rachel Street (Las Cumbres Observatory) — The Role and Strengths of Gravitational Microlensing for Exoplanet Detection and Characterization
                        • Yossi Shvartzvald (JPL/Caltech) — Microlensing Theory and Observables
                        • Calen Henderson (JPL/Caltech) — Extracting Physical Parameters from Microlensing Observables
                        • Jennifer Yee (Smithsonian Astrophysical Observatory) — Recent Microlensing Results
                        • Scott Gaudi (The Ohio State University) — The Future of Exoplanetary Microlensing
                        • The following references provide some background information for the hands-on sessions:

                          If you are participating in the hands-on sessions, please follow these Instructions for Installing VNC, before Wednesday, Aug. 9.

                          Remember to bring the power source for your computer. Also, if you will be using a MacBook Air or tablet for the hands-on sessions, remember to bring an ethernet adaptor.

                          Click here for information and presentations from previous summer workshops.


                          (last updated September 8th, 2017 12:26:58)