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NASA seeks help from Notre Dame physics professor

EMILY McCONVILLE | Wednesday, October 30, 2013


One Notre Dame professor has been asked to directly lend his expertise to the efforts of NASA to find inhabitable planets beyond our solar system.


NASA has named Notre Dame Assistant Professor of Physics Justin Crepp as one of 11 Kepler Participating Scientists, a role in which he will join the Kepler Mission’s search for extrasolar planets capable of supporting life. 

Crepp will study the readings of the Kepler spacecraft, which detects possible planetary bodies orbiting stars thousands of lights years away and flags them as Kepler Objects of Interest (KOIs). 

Crepp said Kepler works by measuring the intensity of each stars’ light and detecting any changes. When a planet passes in front of a star, it creates a kind of “shadow” perceptible to the spacecraft. This process requires that Kepler measure a large number of stars, he said. 

Crepp said such planets can only be detected under specific and fortunate circumstances.

“You have to be lucky in the sense that the planet has to be just at the right orientation that, relative to you, it’s blocking the star,” Crepp said. “If it has a face-on orbit, then you’re never going to see it. So we figure out the geometry and the probability of a planet passing in front of a star, and it depends on the size of the planet and how far away it is, et cetera et cetera. Kepler finds those fortuitous events, we make a list of [Kepler Objects of Interest] KOIs, and then we study those KOIs individually.” 

Each KOI could be etiher a planet or a kind of “false positive,” such as a binary system in which two stars revolve around each other, Crepp said. 

Crepp said his and Notre Dame’s access to the Large Binocular Telescope in Arizona, which has been used to look at some of the thousands of KOIs that Kepler detects and identify them as planets, helped him in his application to be a Kepler Participating Scientist. 

“My particular role is to do imaging follow-up of any stars that Kepler seems to find as potentially interesting,” Crepp said.  

In addition to working with the Kepler mission, Crepp said he is working on a proposal to develop an instrument that detects planets orbiting small stars that are nearer to Earth – Kepler can only detect those that are more than 1,000 light-years away. He said the new instrument would use the Doppler method to measure the “wobble” of stars as the stars’ and planets’ gravitational fields affect one another. 

The ultimate goal of developing such a device is to find nearby planets with the right characteristics, including a sufficiently developed atmosphere, to support extraterrestrial life, Crepp said.