Studying Exoplanets with DEMONEX

March 23, 2011
Jason Eastman's self-built telescope DEMONEX

Early in his astronomy graduate education, Jason Eastman began an extensive project: observing hundreds of exoplanets using his telescope, the Dedicated Monitor of Exotransits telescope, or DEMONEX.

Exoplanets are planets that do not belong to our Solar System but are found in other planetary systems many light years from Earth. Like the name implies, DEMONEX collects information on the transits of exoplanets whose fortuitous orbits place them in front of their host star at certain opportune times. “When the planet moves across the star, it causes a very slight dip in the brightness of the star, which we can use to determine the precise properties of the system,” explained Eastman.   

Eastman works with associate professor Scott Gaudi, who is highly involved with exoplanet research worldwide and was named one of the “10 Rising Stars of Astronomy” by Astronomy Magazine in 2009. “It was Gaudi’s idea to build and name the telescope DEMONEX,” said Eastman. “Our motivation for this project is to get a nice global picture that will refine researchers’ notions of planet formation and evolution,” he continued.

When hunting for exoplanets became a popular pastime after the first exoplanet discovery in the 1990’s, there were no consistent methods for collecting information. Over the last two decades, more than 500 exoplanets have been discovered with different observing techniques and different telescopes. “It’s difficult to study a large number of exoplanets when they have been observed with different instruments. Each telescope has a different sensitivity to light, which makes it very hard to obtain a homogeneous set of processed data,” explained Eastman.

Jason Eastman standing next to the telescope DEMONEX.Eastman’s work with DEMONEX will remedy this problem by gathering a large collection of exoplanets that have been observed using the same instrument and method. In order to achieve this goal, Eastman programs DEMONEX to observe known planetary systems whose planets cross in front of their star. This method is known as the transit method, and it is one of the most widely used techniques for studying exoplanets.

While DEMONEX is primarily used to look at known exoplanets, it could also detect earth-like planets, indirectly. Finding an earth-like planet would not only inspire a new generation of exoplanet discovery, but it would bring researchers that much closer to detecting a planet with ideal conditions for sustaining complex life forms

“It is more likely that the space telescope designed for exoplanet discovery, Kepler, will find an earth-like planet sooner than us. However, it is possible to detect a small mass exoplanet from the ground because of the planet’s slight gravitational influence on its more massive neighbors,” said Eastman. “Using ground-based telescopes also has the benefit of being less expensive and more readily accessible than space telescopes,” he continued.

Unlike traditional observing runs that only last an average of one to three weeks, Eastman observes with DEMONEX year around. “I basically collect data every night when the weather allows it,” he said.

Constant access to a telescope is a great advantage, because it allows Eastman to view planetary systems that are only visible during certain times of the year. DEMONEX is located at the Winer Observatory in Sonoita, Arizona, nearly 2,000 miles from where Jason receives the data at Ohio State.

 “A typical day for me is spent working with computer software to study the data coming in from DEMONEX. It took nearly a year to get it up and running, but I now have a tremendous amount of material that I can’t wait to analyze,” he continued.

Jason Eastman stand next to DEMONEX after it has been mounted.“Something I did not expect was the amount of software I would have to write so that the telescope would automatically observe on its own,” he said.

DEMONEX has been observing for three consecutive years, and it has recorded more than 600 planetary transits and nearly 140 other events. These other observations include cosmic occurrences such as supernovae, which have helped contribute to Eastman’s fellow graduate students’ work.

After he graduates from Ohio State in 2011, Eastman will continue using DEMONEX at his job with the Las Cumbres Observatory near Santa Barbara, California. He will be part of a large network of robotic telescopes collaborating in the search for and study of exoplanets.

Written by Jessica Orwig