Tiny scope spies distant planet
Ron Cowen
Using a telescope not much bigger than the one Galileo invented nearly 400 years ago, astronomers have discovered a planet orbiting a star 500 light-years from Earth. The 4-inch telescope in the Canary Islands is one of three small, globally separated telescopes that monitor the brightness of some 12,000 stars in the constellation Lyra. Periodic dips in brightness can result from an orbiting planet crossing in front of a star.
DISTANT ORB. Artist's depiction of a newly discovered extrasolar planet, flanked by asteroids, as it orbits its parent star.
D.A. Aguilar/Harvard-Smithsonian
Searching for such planetary transits with the Canary Islands telescope, Roi Alonso of the Astrophysical Institute of the Canary Islands found evidence of a Jupiter-size planet whipping around a sunlike star every 3.03 days.
"The discovery demonstrates that even humble telescopes can make huge contributions to planet searches," says discovery team member Guillermo Torres of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. The two other telescopes in the Trans-Atlantic Exoplanet Survey (TrES) network reside at Palomar Observatory near Escondido, Calif., and at Lowell Observatory in Flagstaff, Ariz.
Alonso, Torres, and their coworkers relied on much larger telescopes to verify the transit and to obtain a spectrum of the affected star. The spectrum clinches the finding because it reveals that the star wobbles back and forth in response to the gravity of an unseen planet, the researchers report in an upcoming Astrophysical Journal Letters.
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References:
Sobrino, R.A. … G. Torres, et al. In press. TrES-1: The transiting planet of a bright K0V star. Astrophysical Journal Letters.
Further Readings:
2004. Network of small telescopes discovers distant planet. Lowell Observatory press release (Aug. 24). Available at http://www.lowell.edu/press_room/releases/recent_releases/TrES-1_rls.html.
Cowen, R. 2004. One of Hubble's tools fails. Science News 166(Aug. 14):101. Available to subscribers at http://www.sciencenews.org/articles/20040814/fob5.asp.
______. 1999. Extrasolar planets: Out of the shadows. Science News 156(Nov. 20):324. Available at http://www.sciencenews.org/pages/sn_arc99/11_20_99/fob1.htm.
Sources:
Rio A. Sobrino
Instituto de Astrofísica de Canaries
38200 La Laguna, Tenerife
Spain
Guillermo Torres
Harvard-Smithsonian Center for Astrophysics
60 Garden Street
Cambridge, MA 02138
From Science News, Volume 166, No. 14, October 2, 2004, p. 222.
