Kepler Spacecraft Takes Pulse of Distant Stars

October 28, 2010 — Scientists this week announced the detection of stellar oscillations, or "starquakes," that yield new insights about the size, age and evolution of stars. The results were presented at a news conference at Aarhus University in Denmark by scientists representing the Kepler Asteroseismic Science Consortium. The team studied thousands of stars observed by Kepler, releasing what amounts to a roster of some of humanity's most well-characterized stars. Analysis of stellar oscillations is similar to how seismologists study earthquakes to probe the Earth's interior. This branch of science, called astroseismology, produces measurements of stars the Kepler science team is anxious to have. "Using the unparalleled data provided by Kepler, KASC scientists are quite literally revolutionizing our understanding of stars and their structures," said Douglas Hudgins, Kepler program scientist. "What's more, they are doing so at no cost to the American taxpayer. All the KASC scientists are supported by research funding from their home countries.” In the results presented Tuesday, one oscillating star took center stage: KIC 11026764 has the most accurately known properties of any star in the Kepler field. In fact, few stars in the universe are known to similar accuracy. At an age of 5.94 billion years, it has grown to a little over twice the diameter of the sun and will continue to do so as it transforms into a red giant. The oscillations reveal that this star is powered by hydrogen fusion in a thin shell around a helium-rich core. "We are just about to enter a new area in stellar astrophysics," said Thomas Kallinger, lead author on a study of red giant stars and postdoctoral fellow at the Universities of British Columbia and Vienna. "Kepler provides us with data of such good quality that they will change our view of how stars work in detail." Launched in March 2009, Kepler was designed to discover Earth-size planets orbiting other stars. The spacecraft uses a huge digital camera, known as a photometer, to continuously monitor the brightness of more than 150,000 stars in its field of view as it orbits around the sun. Kepler searches for distant worlds by looking for "transits," when a planet passes in front of a star, briefly causing it to dim. The amount of dimming reveals the size of the planet compared to the size of the star.

Artist's rendition of Kepler spacecraft. Credit: NASA/Kepler mission/Wendy Stenzel This is Kepler's field of view superimposed on the night sky. Credit: Carter Roberts

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