The STEPUP research team is headed by Professor Wood-Vasey at the University of Pittsburgh and consists of 6 undergraduate students led by graduate student Melanie Good. Our goals are to observe and confirm suspected transiting planets and participate in research collaborations as well as to provide a meaningful research experience for undergraduate

students.

Light curve of HD80606 Courtesy Maya HuntHD80606 transit simulation Courtesy Eric Roebuck

MethodThe team observes the brightness of a star as the planet passes between the star and our line of sight. Using the 16” RCX-400 Meade telescope equipped with an SBIG 0.”56 per pixel CCD at the Allegheny Observatory, STEPUP takes multiple images of a star and measures its brightness over time. An observed decrease in brightness may indicate the passing of an orbiting planet that is blocking a small percentage of the star’s light. By observing a star over many nights, the team can determine the orbital period, the radius, and the orbital inclination of the planet.

Artistic rendition of transit and graph of brightness vs time. Courtesy CNES

The STEPUP teamFront from left: grad student Melanie Good, Maya Hunt, Gwen

Weaver, and Korena Costello Back from left: Gary Lander, Dr. Michael Wood-Vasey, Nelson Hua.

Observatory UpgradesUndergraduate team members have recently installed an all-sky camera and a cloud sensor, which provide images of sky conditions for observers. They have also motorized the Meade dome and shutters to allow for fully remote observing from the University of Pittsburgh main campus. The team will next renovate the historic Thaw telescope to enable observations of more distant stars.

Data Analysis and SimulationsSTEPUP analyzes data using programs written in IDL. These programs take raw images of extra-solar planetary systems, calibrate them based on the properties of an individual night, and measure the brightness of the star as compared to reference stars. This process yields a light curve, a graph describing the change in brightness of the host star during transit. Using models by Eric Agol at the University of Washington, the team has simulated light curves of transiting planets. These simulations can be used to help predict the possible times of future transits. Below is a light curve and simulation of the transit in front of the star HD80606.

AbstractThe STEPUP team assembled with the goal of observing planets eclipsing their host stars (transiting planets). The various aspects of our project include data analysis and collection, programming, observatory hardware, and public outreach/education. To date we have observed eight known transiting planets and three potential targets. Using these data, we have helped confirm several known extra-solar planets and constrain their orbital parameters.

Undergraduates Korena Costello and Gary Lander work to automate the Keeler dome

Special Thanks to the University of Pittsburgh Department of Physics and Astronomy, Dr. Wood-Vasey, Lou Coban and the Allegheny Observatory.

Poster by Gwen Weaver. Background Image Allegheny Observatory

Future WorkThe team’s current goals include improving data analysis, participating in international collaborations to discover new transiting extra-solar planets, arranging educational sessions at local schools, and updating the Thaw telescope for future work.

The Keeler telescope

Special Thanks

STEPUPSurvey of Transiting Extrasolar Planets of the University of Pittsburgh