Courtesy of Christopher Colarosa
Astronomers at Ohio State are going to be able to look, with some of the largest cameras ever made, into space to find undiscovered planets.
Four OSU astronomers were awarded a $5 million contract from the Korea Astronomy and Space Sciences Institute. They will build three 340-megapixel cameras for KASI that are to be mounted on a telescope to examine space to find planets.
OSU competed against other teams in different states and countries for the award.
Andrew Gould, the Thomas Jefferson Professor for Discovery and Space Exploration and the mediator between engineers and scientists for this project, said their team had the upper hand.
“Our bid was likely to be extremely competitive because of better knowledge of the project and the organization of our labs,” Gould said. “The lab is dedicated to scientific missions and, you know, not profits … So it’s able to take a long-term view and it’s not just trying to poach different projects.”
The astronomers worked with KASI in 2008 to find out what they were going to accomplish. Chengho Han, a Ph.D. graduate from OSU in 1997 and Korean scientist of Chungbuk National University, helped OSU with this project.
Gould said the overall goal of the project is to find planets, such as free-floating planets that have been knocked out of orbit, by use of gravitational microlensing.
“If two stars get lined up really closely, the one in front is going to bend the light from the one in back and magnify it,” Gould said. “And that means if you are watching this star, even if you can’t see that star, the star comes by and when it gets really close, the star is going to get brighter.”
These light curves can be analyzed from the camera and there is only one in a million stars that will be magnified, he said. If there is a planet near the star, the planet’s gravity enhances the light from the star and will create a “blip,” which can be used to find that planet.
Gould said he was one of the pioneers of this method.
“Twenty years ago when people first started doing this, I personally developed another method that people are using today to find the planets,” Gould said. “After they find these microlensing events, they announce them and then other people get smaller telescopes and just look at those events. They’re not trying to find them – they already know where they are.”
These events are extremely rare to see and were even disproved by Albert Einstein in 1912. Rudi Mandl, a scientist from Czechoslovakia, in 1936 told Einstein to re-evaluate his thinking. Einstein doubted these events even after he published his work.
Jennifer Yee, a graduate fellow in astronomy and Gould’s assistant, helps him with this work because of how complicated it can be.
“I work intensively on finding planets with microlensing, but not specifically related to this camera,” Yee said. “The knowledge is related – they are all tangled up by each other.”
Yee and Gould have worked together on these other projects and so far have discovered between 15 and 20 planets. They also work together by setting up the network between all the different countries involved.
The Korea Microlensing Telescope Network is the process by which this project is going to work. The connections are found in Chile, Australia and South Africa. These are the areas where the three cameras are going to be placed, because of the different time zones, they can survey 24 hours.
Bruce Atwood, research and project scientist, is helping build the electronics for the camera and said it’s a long process because of its magnitude.
“We have to deliver the first of three cameras in July of next year,” Atwood said. “The camera is about 20 inches in diameter … the lens is about 12 to 13 inches in diameter. … There are lots and lots of pieces.”
One of these pieces is the Dewar flask, named after James Dewar, a Scottish chemist and physicist. It works like a thermos and keeps the camera cold, near minus 200 C, so it doesn’t overheat from too much light. This device helps scientists get long exposures of the solar system, so they’re able to see much more than they could before.
Another interesting facet of the camera is the charge coupled device, which is the most important part of the camera because it lets in the light and records the images, Atwood said. These CCDs will be some of the largest ever made so it can get the 340 megapixels.
Microlensing became more known during the 1980s, when Bohdan Paczynski, a Princeton professor, said these CCDs, which are in every camera, could be used to take pictures of the stars.
KASI has jurisdiction over the project and it makes sure the work done to the contract is successful.
Sang-Mok Cha, KASI employee, is at OSU overseeing the project and relaying the progress back to Korea.
The other scientists on this project are Tom O’Brien, research specialist in astronomy and project engineer, and Scott Gaudi, associate professor of astronomy.
The cost of this project is about $30 million for the Koreans and it is a major commitment for them since the United States currency is higher than theirs. OSU must stay on target with their contract and make sure they outline all their expenses finely.
Despite the extreme cost, Gould said he is hopeful for this project and looks forward to its completion around June 2014.
“The KMTN is going to revolutionize things by just having an entire system that’s been designed from scratch in order to be able to do this,” Gould said.