Novel Camera Set to Produce the First Direct Images of Extrasolar Planets

June 8, 2004
Laird Close pictured with four identical green laser SDI images. "The team that gets the first direct picture of an extrasolar planet will be the team that's cleverest with optics, cleverest with software, and cleverest with a telescope, " Close said.
Laird Close pictured with four identical green laser SDI images. "The team that gets the first direct picture of an extrasolar planet will be the team that's cleverest with optics, cleverest with software, and cleverest with a telescope, " Close said.
This extraordinary view of  Saturn's moon, Titan, was produced with an Earth-based telescope using a new kind of camera developed by UA astronomer Laird Close. Titan is about 800 million miles away. The resolution of this image is 360 kilometers, about 200 miles. (Photo: Markus Hartung, ESO, and Laird Close, UA Steward Observatory)
This extraordinary view of Saturn's moon, Titan, was produced with an Earth-based telescope using a new kind of camera developed by UA astronomer Laird Close. Titan is about 800 million miles away. The resolution of this image is 360 kilometers, about 200 miles. (Photo: Markus Hartung, ESO, and Laird Close, UA Steward Observatory)

A University of Arizona astronomer and his collaborators are using a novel camera to hunt for extrasolar planets.

Their camera has already made stunning images of Saturn's moon, Titan, and discovered an object just 27 times the mass of Jupiter. They hope the camera will be the first to directly photograph faint gas-giants similar to Jupiter in solar systems beyond our own.

The project is being funded over the next five years by a $545,000 National Science Foundation award. NSF awarded the highly competitive Faculty Early Career Development (CAREER) award to Associate Professor Laird M. Close. The CAREER program is a foundation-wide activity that offers the NSF's most prestigious awards for new faculty members. The program recognizes and supports the early career-development activities of those teacher-scholars who are most likely to become the academic leaders of the 21st century.

Close and his graduate students, Beth Biller and Eric Nielsen, will use Close's custom SDI (Simultaneous Differential Imager) cameras on two big telescopes in Arizona and Chile to hunt for planets orbiting other stars.

Astronomers have indirectly detected more than 100 planets circling stars in other solar systems, but none have yet been directly imaged.

Close plans to solve the problem of detecting faint planets near their billion-times-brighter stars by using a unique, high-contrast, SDI camera. The camera uses adaptive optics, which remove the blurring effects of the Earth's atmosphere and produce extremely sharp images.

The SDI camera splits light from a single object into four identical images, then passes the resulting beams through four slightly different methane-sensitive filters. When the filtered light beams hit the detector array, astronomers can subtract the images so the bright star disappears, revealing the massive, methane-rich planet.

Professor Close and his collaborators will use SDI to examine 100 young northern- and southern-hemisphere stars that are near Earth. They will hunt for planets as small as 3 Jupiter masses (three times the mass of Jupiter) that are as close as 5 AU from their stars. This is about the distance between Jupiter and the sun. One "AU," or astronomical unit, is the distance between Earth and the sun.

The northern SDI camera will be used on the 6.5-meter, UA/Smithsonian, MMT telescope on Mount Hopkins, Ariz, in collaboration with Steward Observatory astronomer Donald McCarthy. The southern SDI camera has been installed at the European Southern Observatory's (ESO) 8.2-meter Very Large Telescope (VLT) in Chile. Astronomers Rainer Lenzen and Wolfgang Brandner of the Max-Planck-Institut f