University of Hawaii Instutute for Astronomy
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EMBARGOED UNTIL: 7:00 am HST (1:00 pm EDT) May 18, 2006


Dr. James Heasley
Institute for Astronomy
University of Hawaii at Manoa
Honolulu, Hawaii 96822

Mrs. Karen Rehbock
Assistant to the Director
Institute for Astronomy
University of Hawaii at Manoa


Institute for Astronomy
Director's office
2680 Woodlawn Drive Honolulu, Hawaii 96822
Telephone: 1-808-956-8566
Fax: 1-808-946-3467

Maintained by LG


Haleakala Telescope Finds Planet

The XO telescope on the summit of the Haleakala looks like a large pair of binoculars. Credit: NASA, ESA, and J. Stys (STScI)

An international team of astronomers has used a small, automated telescope located on Haleakala to discover a planet orbiting a Sun-like star 600 light-years from Earth.

The team, led by Peter McCullough of the Space Telescope Science Institute in Baltimore, includes UH astronomer James Heasley. They used a relatively inexpensive telescope made from off-the-shelf components to scan the skies for extrasolar planets. Called the XO telescope, it consists of two 200-millimeter telephoto camera lenses and looks like a pair of binoculars.

The team found the planet, dubbed XO-1b, by noticing two percent dips in the star's light output when the planet passed in front of the star. The observation also revealed that XO-1b is in a tight four-day orbit around its parent star, which is in the constellation Corona Borealis.

Heasley stated, “In the future, we can use small telescopes such as XO to find out where planets around stars may be, and larger telescopes such as those on Mauna Kea to confirm such discoveries.”  The team confirmed XO-1b's existence by using the Harlan J. Smith Telescope and the Hobby-Eberly Telescope at the University of Texas's McDonald Observatory to measure the slight wobble induced by the planet on its parent star. This so-called radial-velocity method allowed the team to calculate a precise mass for the planet, which is slightly less than that of Jupiter (about 0.9 Jupiter masses).

University of Hawaii staff members on Maui who made operation of the XO telescope possible include Bill Giebink, Les Hieda, Jake Kamibayashi, Daniel O’Gara, and Joey Perreira.

For more information, see the following Web sites:
Space Telescope Science Institute:
McDonald Observatory:
Rice University:
Boston University:


Astronomers used this inexpensive telescope to find an extrasolar planet transiting the face of a Sun-like star 600 light-years from Earth. The telescope, which looks like a pair of binoculars, consists of two 200-millimeter telephoto camera lenses. The lenses are attached to electronic devices that measured slight dips in light output from the star, indicating that an object was crossing in front of it. The telescope is on the summit of the Haleakala on Maui. Credit: NASA, ESA, and J. Stys (STScI)

The Institute for Astronomy at the University of Hawaii conducts research into galaxies, cosmology, stars, planets, and the sun. Its faculty and staff are also involved in astronomy education, deep space missions, and in the development and management of the observatories on Haleakala and Mauna Kea.

Established in 1907 and fully accredited by the Western Association of Schools and Colleges, the University of Hawaii is the state's sole public system of higher education. The UH System provides an array of undergraduate, graduate, and professional degrees and community programs on 10 campuses and through educational, training, and research centers across the state. UH enrolls more than 50,000 students from Hawaii, the U.S. mainland, and around the world.




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