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RE: The Pleiades
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The Seven Sisters, also known as the Pleiades, seem to float on a bed of feathers in a new infrared image from NASA's Spitzer Space Telescope. Clouds of dust sweep around the stars, swaddling them in a cushiony veil.

Pleiades
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This image is made up of data taken by Spitzer's multiband imaging photometer and its infrared array camera. Light with a wavelength of 4.5 microns is blue; light of 8 microns is green; and light of 24 microns is red.
Credit NASA


Position (J2000): RA: 3h 47m 00s Dec: +24d 00m

The view is quite different from what you might see if you look out to the west shortly after dusk. Right now, the famous family of stars is "stepping out" in the evening skies with a very bright and dazzling Venus. During the period from around April 10 to 13, the Pleiades shine like a cluster of diamonds just above Venus. On April 19, the crescent moon will join the party, sliding between Venus and the Pleiades for a special viewing.

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The stars of the Pleiades cluster, also known by the names "M45" and "the Seven Sisters," shine brightly in this view from the Cassini spacecraft currently in orbit around Saturn.

PIA08260
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Credit NASA/JPL

The monochrome view was made by combining 49 clear filter images of the Pleiades taken with the Cassini spacecraft wide-angle camera on Aug. 1, 2006. The images were taken as a part of a sequence designed to help calibrate the camera electronics.

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Title: Spitzer 24 micron Survey of Debris Disks in the Pleiades
Authors: Nadya Gorlova, George H. Rieke, James Muzerolle, John R. Stauffer, Nick Siegler, Erick T. Young, John H. Stansberry (University of Arizona; Spitzer Science Center, Caltech)

Researchers performed a 24 micron 2 Deg X 1 Deg survey of the Pleiades cluster, using the MIPS instrument on the Spitzer Space telescope. Fifty four members ranging in spectral type from B8 to K6 show 24 micron fluxes consistent with bare photospheres. All Be stars show excesses attributed to free-free emission in their gaseous envelopes. Five early-type stars and four solar-type stars show excesses indicative of debris disks.
The researchers find a debris disk fraction of 25 % for B-A members and 10 % for F-K3 ones. These fractions appear intermediate between those for younger clusters and for the older field stars. They indicate a decay with age of the frequency of the dust-production events inside the planetary zone, with similar time scales for solar-mass stars as have been found previously for A-stars.

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