NASA has announced that the Kepler Mission has released the first 43 days of science data on more than 156,000 stars.

Kepler is designed to continuously monitor a star field in the constellations Cygnus and Lyra. The objective is to find Earth like planets circling solar-like stars in what is known as the Habitable Zone, the region around a star where water can exist as a liquid. Since planetary orbits in this region take about a year to complete, the Kepler mission is designed to last through November 2012. This will allow Kepler to catch a planet fitting the description making three transits of its star during the three and a half year mission. Kepler was launched 6 March 2009.

When a planet transits a star, it blocks some of the light from the star. If an observatory is looking at the star at just the right moment, it will see the star dim and then brighten again when the planet finishes passing in front of the star. The effect is very small. A transit will dim the starlight by 100 parts per million, and last from 2 to 16 hours if the planet is in the habitable zone.

Kepler is designed to monitor 100,000 stars continuously for three and a half years. This is enough time to capture three transits by a planet. Kepler has only one instrument on board. This is a 0.95 meter telescope equipped with a photometer. The telescope has a large field of view in order to capture all the stars simultaneously. The field of view is about the size of your hand held at arms length (105 square degrees).

Data from the Kepler mission is archived at Space Telescope Science Institute. The three missions in which the Institute participates are Hubble, the James Webb Space Telescope, and Kepler.

Kepler Diagram
Diagram of the Kepler Spacecraft
Image Credit: NASA

Kepler Photometer
Kepler Photometer Focal Plane Assembly
Image Credit: Ball Aerospace

The photometer (left) is a single instrument, composed of 42 Charge Coupled Devices (CCDs). Each of the square units in the image are two 25 mm x 50 mm CCDs, each comprised of 2200×1024 pixels.

The CCDs are read every three (3) seconds and the data is integrated over 30 minutes. The instrument has the ability to detect an earth sized object transiting a star in 6.5 hours of integrated data.

The instrument has a spectral bandpass from 400 nm to 850 nm. Data from the individual pixels that make up each star of the 100,000 main-sequence stars are recorded continuously and simultaneously. The data are stored on the spacecraft and transmitted to the ground about once per month.

The targeted region of space and the star field in the field of view can be seen here.

At right is the Kepler spacecraft during construction. The size of the Solar Array and the Telescope (wrapped in gold foil) can be seen compared to the technician working on the Solar Array.

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 the percentage of terrestrial and larger planets that are in or near the habitable zone of a wide variety of stars
  • Determine the distribution of sizes and shapes of the orbits of these planets
  • Estimate how many planets there are in multiple-star systems
  • Determine the variety of orbit sizes and planet reflectivities, sizes, masses and densities of short-period giant planets
  • Identify additional members of each discovered planetary system using other techniques
  • Determine the properties of those stars that harbor planetary systems

Kepler with Solar Array (interior)
Image Credit: NASA and Ball Aerospace

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3 thoughts on “Kepler

  1. Pingback: July 2010 « NSS Phoenix Space News

  2. Pingback: 1,235 New Planets « The National Space Society of Phoenix

  3. Pingback: Kepler Planet Candidate Count – 2321 « The National Space Society of Phoenix

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