nasa

Kepler Discovers Two Planets Transiting Same Star

08.26.2010

	Worlds on the Edge. This artist’s concept illustrates the two Saturn-sized planets discovered by NASA’s Kepler mission. The star system is oriented edge-on, as seen by Kepler, such that both planets cross in front, or transit, their star, named Kepler-9. This is the first star system found to have multiple transiting planets.

See full NASA RELEASE : 10-73AR Excerpt:
MOFFETT FIELD, Calif. -- NASA's Kepler spacecraft has discovered the first confirmed planetary system with more than one planet crossing in front of, or transiting, the same star.
The transit signatures of two distinct planets were seen in the data for the sun-like star designated Kepler-9. The planets were named Kepler-9b and 9c. The discovery incorporates seven months of observations of more than 156,000 stars as part of an ongoing search for Earth-sized planets outside our solar system. The findings will be published in Thursday's issue of the journal Science.
... Kepler-9b is the larger of the two planets, and both have masses similar to but less than Saturn. Kepler-9b lies closest to the star with an orbit of about 19 days, while Kepler-9c has an orbit of about 38 days....
"This discovery is the first clear detection of significant changes in the intervals from one planetary transit to the next, what we call transit timing variations," said Matthew Holman, a Kepler mission scientist from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "This is evidence of the gravitational interaction between the two planets as seen by the Kepler spacecraft."
In addition to the two confirmed giant planets, Kepler scientists also have identified what appears to be a third, much smaller transit signature in the observations of Kepler-9. That signature is consistent with the transits of a super-Earth-sized planet about 1.5 times the radius of Earth in a scorching, near-sun 1.6 day-orbit. Additional observations are required to determine whether this signal is indeed a planet or an astronomical phenomenon that mimics the appearance of a transit....
Media Telecon Still Images:
Credit for all images: NASA/Kepler Mission, except as noted.

Worlds on the Edge. This artist’s concept illustrates the two Saturn-sized planets discovered by NASA’s Kepler mission. The star system is oriented edge-on, as seen by Kepler, such that both planets cross in front, or transit, their star, named Kepler-9. This is the first star system found to have multiple transiting planets. Image credit: NASA/Ames/JPL-Caltech.

Kepler spacecraft and light curve illustration. A depiction of the Kepler spacecraft along with a light curve, which is a plot of star brightness versus time. The light curve shows a star dimming as a planet passes in front of it, an event known as a transit.

Bullet points of what Kepler mission is doing.

Expected transit signature of a multiple planet system (transit durations exaggerated).

Light curves of Kepler 9b, 9c, and the Super-Earth candidate.

Animations:

mpeg 13Mb  Animation of Kepler Field of View in Cygnus/Lyra region of the sky, with exaggerated dimming of stars.

Bigger mpeg (43M) --||-- Smaller mpeg (14M). Animation showing difference between planet transit timing of 1-planet and 2-planet systems.

mpeg (3 Mb). Animation of 2-planet system, top view only, showing deviations in orbit of smaller/inner planet caused by gravity interaction with the larger/outer planet

See also media for this story:

• still images
• animations

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