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.

2000 April 7
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Celebrating Hubble With NGC 6751
Credit: A. Hajian (USNO) et al., Hubble Heritage Team (STScI/ AURA), NASA

Explanation: Planetary nebulae do look simple, round, and planet-like in small telescopes. But images from the orbiting Hubble Space Telescope have become well known for showing these fluorescent gas shrouds of dying Sun-like stars to possess a staggering variety of detailed symmetries and shapes. This composite color Hubble image of NGC 6751 is a beautiful example of a classic planetary nebula with complex features and was selected to commemorate the tenth anniversary of Hubble in orbit. The colors were chosen to represent the relative temperature of the gas - blue, orange, and red indicating the hottest to coolest gas. Winds and radiation from the intensely hot central star (140,000 degrees Celsius) have apparently created the nebula's streamer-like features. The nebula's actual diameter is approximately 0.8 light-years or about 600 times the size of our solar system. NGC 6751 is 6,500 light-years distant in the constellation Aquila.

Tomorrow's picture: Compton Anniversary

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