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http://planetquest.jpl.nasa.gov/overview/overview22.swf. by Barbara Brown for ASTR 402 Spring, 2006. Kepler Mission test hypotheses: Most stars like our Sun have terrestrial planets in or near the habitable zone On an average two Earth-size planets form in the region between 0.5 and 1.5 AU.
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by Barbara Brown for ASTR 402 Spring, 2006
Kepler Mission test hypotheses: • Most stars like our Sun have terrestrial planets in or near the habitable zone • On an average two Earth-size planets form in the region between 0.5 and 1.5 AU
What is a habitable planet? • Liquid water on planet surface--determined by size and temperature of the star and orbit of the planet • Size and mass of planet--small planets don’t have enough surface gravity to hold onto a life-sustaining atmosphere • Amount and composition of atmosphere • Affects of moons and giant planets in the system
How are we going to do this? http://kepler.nasa.gov/media/KEPLER.SWF
Kepler Mission Scientific Objective: • The scientific objective of the Kepler Mission is to explore the structure and diversity of planetary systems. This is achieved by surveying a large sample of stars to: • Determine how many terrestrial and larger planets there are in or near the habitable zone of a wide variety of spectral types of stars; • Determine the range of sizes and shapes of the orbits of these planets;
3. Estimate the how many planets there are in multiple-star systems; 4. Determine the range of orbit size, brightness, size, mass and density of short-period giant planets; 5. Identify additional members of each discovered planetary system using other techniques; and 6. Determine the properties of those stars that harbor planetary systems.
Expected Results: • Based on the mission described above and assumption that planets are common around other stars like our Sun, then we expect to detect: • From transits of terrestrial planets: • About 50 planets if most are the same size as Earth (R~1.0 Re), • About 185 planets if most have a size of R~1.3 Re, • About 640 planets if most have a size of R~2.2 Re, • About 12% with two or more planets per system.
From modulation of the reflected light from giant inner planets: • About 870 planets with periods less than one week. • From transits of giant planets: • About 135 inner-orbit planet detections, • Densities for 35 inner-orbit planets, and • About 30 outer-orbit planet detections.
Characteristics of a planetary transit: • Period of recurrence of the transit • Duration of the transit • Fractional change in brightness of the star
How can we detect a planetary transit? http://planetquest.jpl.nasa.gov/science/finding_planets.cfm
What would a transit look like (on a graph)? http://planetquest.jpl.nasa.gov/transit/indexTransit.html
The Kepler instrument: 0.95-meter diameter photometer telescope 105 degrees2 field of view Continuously and simultaneously monitor the brightnesses of more than 100,000 stars for the life of the mission—4 years
Kepler Mission Team Members Scientific Operations Center at NASA Ames: William Borucki, Principal Investigator Mission Operations Center at University of Colorado LASP Data Management Center at Space Telescope Science Institute Industrial partner: Ball Aerospace, Boulder, CO
Resources • http://kepler.nasa.gov • “Close-up on the Kepler Mission” by Jon Jenkins, www.space.com • “Solar transits: Tools of discovery” by Edna DeVore, www.space.com • http://planetquest.jpl.nasa.gov/Kepler/kepler_index.cfm • http://planetquest.jpl.nasa.gov/transit/indexTransit.html • http://www.ballaerospace.com/kepler.html • “Detecting other worlds:The photometric transit or 'Wink' method” by Dr. Laurance Doyle, www.seti.org • http://photojournal.jpl.nasa.gov/gallery/universe