Planet Hunters

PHYS 199 - Fall semester orientation for Physics majors


1. Learning objectives:

  • Students will learn to manipulate data from NASA Kepler’s Space Telescope using the graphical interface provided by Zooniverse’s Planet Hunter website.
  • Students will understand the concept of a time series for stellar brightness data.
  • Student will understand the concept of “planetary transit” and related techniques to search for new extrasolar planet in Kepler’s database.
  • Students will learn how to synthesize informations from a variety of astronomy-related websites to learn new astronomy techniques.
  • Students will work in teams to prepare presentation with results of their work.


2. Context:

  • Research module for Physics Majors interested in astronomy and enrolled in PHYS 199 (orientation course, freshmen fall semester). Typically 6-8 students out of all freshmen Physics Majors.
  • Entire module lasts ½ semester (last 7 weeks of fall semester).
  • Students work individually on Kepler’s data time series, then compare results among themselves and with instructors in bi-weekly meetings.
  • Students work in team to research astronomy techniques used in extrasolar planets research, and prepare group presentation.


3. Resources:


4. Teaching Notes and Tips

The students do most of their research on their own time: in class we only give them an overview about the science and datasets, and a brief introduction about the web site. This gets them started. The Planet Hunters web site has a very good online tutorial, which they can go through on their own before we meet for the second time. Since the research activity is done outside of class, it is important to monitor the students progress in the previous weeks at each meeting, giving them detailed goals and explaining clearly what they are expected to deliver before each class.

It is very easy for the students too get caught up in the “game” aspect of the project, competing with each other to analyze more datasets. To make them think about what they are doing, and introduce them to the concept of serendipitous discoveries in science, we encourage each student to flag datasets that they find peculiar (not conforming to the expected standard as seen in the tutorial), for discussion next time we meet. These datasets are most commonly associated to variable stars of different kinds (although there may be cases that even the instructors cannot readily explain). The examples brought in by the students are then discussed in class, and possible hypothesis are examined to explain their features. This is a good occasion to introduce other topics in stellar astrophysics (stellar variability, stellar pulsations, binary stars, etc), and the general process in which scientific hypothesis are examined and validated with actual data.

We try to stimulate the interest of the students in astronomy by having them meet with an expert working in the field. This is either a visitor coming to the department for other reasons, or they meet with Prof. Kawaler, who is part of the Kepler’s team. Several of the students that in the past have taken part of this module ended up doing the minor in astronomy offered by our department.


5. Description of activities:

  • Students learn how to use the Planet Hunters analysis tool going through the tutorials offered by the web site. Instructor explains how the “transit method” works, and how can be used to identify extrasolar planets passing in front of the stars.
  • Students are presented with light curves (time series with stellar brightness data) for a number of targets selected randomly from a catalog of ~150,000 stars. Using the Planet Hunters tools they flag possible transits and save data for all stars they find with peculiar light curves.
  • Results are discussed in class: students propose tentative explanations for the observed peculiarity in flagged light curves. Explanations are discussed in group and with instructors, and provide motivations to understand basic physics of stellar variability.
  • Students are divided in pairs and tasked with researching other techniques (using non-Kepler data) for extrasolar planets detection. Students are directed to a number of NASA and astronomy web sites (and Wikipedia) to research the subject. Students are encouraged to investigate strengths and weaknesses of different methods, and when they are best applicable. Results are discussed in class with other students and instructors at the end of the presentation.
  • Each team compiles a brief powerpoint presentation to explain the method they have researched to the other students working in the Planet Hunters project.
  • Students present overall activity and results at the end-of-semester meeting of all PHYS 199 students.


7. Assessment

None currently available.


8. References

Similar courses have been performed at Austin College, Hartnell College, and U.C. Santa Cruz



Dr. Massimo Marengo, Professor of Astronomy

Dr. Charles Kerton, Assistant Professor of Astronomy