Redfield Speaks to Wesleyan Staff about Discovering Exoplanets

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On Oct. 31, Seth Redfield, associate professor of astronomy, spoke on “Blue Skies on Distant Worlds” during a special luncheon for staff in Daniel Family Commons. Redfield, whose research interests focus on exoplanets and their atmospheres, explained how astronomers can detect and measure planets outside of our solar system. In the same way Earth orbits around the sun, an exoplanet will circle around a star. For some planetary systems, from Earth, astronomers can view the the exoplanet passing directly in front of its host star once per orbit.

“The transit of the exoplanet not only provides a means of detecting the planet and measuring its size, but also enables us to measure starlight passing through, or being blocked, by the exoplanetary atmosphere,” Redfield explained. He demonstrated how Venus's transit, in 2012, appeared from Earth. 

“The transit of the exoplanet not only provides a means of detecting the planet and measuring its size, but also enables us to measure starlight passing through, or being blocked, by the exoplanetary atmosphere,” Redfield explained. He demonstrated how Venus’s 2012 transit appeared from Earth.

Redfield is particularly interested in Alpha Centauri, the closest star system to our solar system, and the exoplanetary atmosphere of HD 189733 b, an extra solar planet. Redfield was the first astronomer to make ground-based detection of HD189733 b's atmosphere using a telescope.

Redfield is particularly interested in Alpha Centauri, the closest star system to our solar system, and the exoplanetary atmosphere of HD 189733 b, an extra solar planet. Redfield was the first astronomer to make ground-based detection of HD189733 b’s atmosphere using a telescope.
In addition, Redfield is able to take spectral observations in these exoplanet atmospheres and look for certain biomarkers, which may indicate the existence of life. “By examining the spectrum data, we can see signatures of life, which might make it easier to find life on an exoplanet.”

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“In the next 100 years, or even in our lifetime, we will be looking for life on other planets and I find it exciting and compelling and I am glad to be part of it,” Redfield said to the audience. (Photos by Olivia Drake)