Public Release: 

Massive transiting planet with 31-hour year found around distant star

Lowell Observatory

Flagstaff, Ariz. -- An international team of astronomers with the Trans-atlantic Exoplanet Survey today announce the discovery of their third planet, TrES-3. The new planet was identified by astronomers looking for transiting planets - that is, planets that pass in front of their home star - using a network of small automated telescopes in Arizona, California, and the Canary Islands. TrES-3 was discovered in the constellation Hercules about 10 degrees west of Vega, the brightest star in the summer skies.

"TrES-3 is an unusual planet as it orbits its parent star in just 31 hours!," said Georgi Mandushev, Lowell Observatory astronomer. "That is to say, the year on this planet lasts less than one and a third days. It is also a very massive planet - about twice the mass of the solar system's biggest planet, Jupiter - and is one of the planets with the shortest known periods."

The new planet TrES-3 was first noticed by Lowell Observatory's Planet Search Survey Telescope (PSST), set up and operated by Edward Dunham and Georgi Mandushev. The Sleuth telescope, maintained by David Charbonneau (CfA) and Francis O'Donovan (Caltech), at Caltech's Palomar Observatory also observed transits of TrES-3, confirming the initial detections. TrES-3 is about 1,500 light-years distant and because it is so close to its host star, it is very hot, about 1,500 degrees Kelvin.

"TrES-3 will be an intriguing object to study more deeply, said Edward Dunham, Lowell Observatory instrument scientist. "For example, its tight orbit causes it to be illuminated very strongly. This may make it possible to measure the variation in reflected light as it goes through its phases. This will tell us how reflective its atmosphere is."

By definition, a transiting planet passes directly between Earth and the star, causing a slight dimming of the star's light in a manner similar to that caused when the moon passes between the Sun and Earth during a solar eclipse. To look for transits, the small telescopes are automated to take wide-field timed exposures of the clear skies on as many nights as possible. When an observing run is completed for a particular field - usually over an approximate two-month period - astronomers measure very precisely the light from every star in the field in order to detect the possible signature of a transiting planet. "TrES-3 blocks off about 2.5 percent of the light of the star as it passes in front of it," said Mandushev. "With our telescopes, we can measure this tiny drop in the star's brightness and deduce the presence of a planet there."

TrES-3 was also observed by members of the Hungarian Automated Telescope Network (HATNet). The study's lead author, Francis O'Donovan of Caltech, highlighted the teamwork between TrES and HAT. "The search for extrasolar planets is an exciting and competitive field. I was happy to see that cooperation between separate teams led to a rapid confirmation of this planet," said O'Donovan.

In order to help confirm they had found a planet, HATNet's Gaspar Bakos and CfA's Guillermo Torres switched from the 10-centimeter TrES telescopes to one of the 10-meter telescopes at the W. M. Keck Observatory on the summit of Mauna Kea, Hawaii. Using this giant telescope, they confirmed that they had found a new planet. In order to measure accurately the size and other properties of TrES-3, astronomers also made follow up observations of it with bigger telescopes at Lowell Observatory and Fred L. Whipple Observatory in Arizona, and with the Las Cumbres Observatory Global Telescope in Hawaii.

###

Other authors of the paper "TrES-3: A Nearby, Massive, Transiting Hot Jupiter in a 31-hour Orbit," accepted for publication in the Astrophysical Journal, are Gaspar Bakos, David Charbonneau, David Latham, Alessandro Sozzetti, Robert Stefanik, and Guillermo Torres of the Harvard-Smithsonian Center for Astrophysics; Timothy Brown, Nairn Baliber, and Marton Hidas of the Las Cumbres Observatory Global Telescope; Geza Kovacs of Konkoly Observatory in Hungary; Mark Everett and Gilbert Esquerdo of the Planetary Science Institute; Markus Rabus, Hans Deeg, and Juan Belamonte of the Instituto de Astrofisica de Canaries in Tenerife, Spain; and Lynne Hillenbrand of the California Institute of Technology. The paper is available online at: http://arxiv.org/abs/0705.2004.

This research is funded by NASA through the Origins of Solar Systems Program.

About Lowell Observatory

Lowell Observatory is a private, non-profit research institution founded in 1894 by Percival Lowell. The Observatory has been the site of many important findings including the discovery of the large recessional velocities (redshift) of galaxies by Vesto Slipher in 1912-1914 (a result that led ultimately to the realization the universe is expanding), and the discovery of Pluto by Clyde Tombaugh in 1930. Today, Lowell's 19 astronomers use ground-based telescopes around the world, telescopes in space, and NASA planetary spacecraft to conduct research in diverse areas of astronomy and planetary science. The Observatory welcomes 70,000 visitors each year to its Mars Hill campus in Flagstaff, Arizona for a variety of tours, telescope viewing, and special programs. Lowell Observatory currently has four research telescopes at its Anderson Mesa dark sky site east of Flagstaff, and is building a 4-meter class research telescope, the Discovery Channel Telescope, in partnership with Discovery Communications, Inc.

Editors: view and download the computer generated simulation to accompany this release at http://www.lowell.edu/press_room/TrES-3_images.html

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.