Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

April 22, 1998
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HR 4796A: A Recipe for Planets
Credit: C. Telesco (U. Florida) et al. (CfA, NOAO), OSCIR, Keck II

Explanation: Two hundred and twenty light years from Earth, planets are forming. Recent observations of the binary star system HR 4796 have shown that one of the stars is surrounded by a dusty gaseous disk. This disk is of the right size, age, and density for dust pellets to accrete surrounding matter. A hole in the disk's center indicates that increasingly larger condensates are colliding and sticking together, coalescing into moons and planets. Pictured above is a false-color image of the system, with the bright star HR 4796A indicated by a cross. The disk measures about five times the size of our Solar System, and is seen nearly edge-on. HR 4796 is in the southern constellation Centaurus.

Tomorrow's picture: A Dust Disk Around Vega

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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