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.

June 22, 1999
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PKS285-02: A Young Planetary Nebula
Credit: R. Sahai & J. Trauger (JPL), WFPC2, HST, NASA

Explanation: How do planetary nebulae acquire their exquisite geometrical shapes? To investigate this, astronomers used the Hubble Space Telescope to image several young planetary nebulae. These nebulae are the outer envelopes of stars like our Sun that have recently been cast away to space, leaving behind a core fading to become a white dwarf. In this photograph in red H-alpha light, very young planetary nebula PKS285-02 is seen surrounded by unusual expanding shells only thousands of years old. Much of the carbon that composes humans is thought to be created by red giant stars and ejected into the cosmos in planetary nebulae like PKS285-02. The complexity of this nebula leads some astronomers to hypothesize that these shells were created by high-speed, collimated outflows during a late phase of this star's evolution.

Tomorrow's picture: A Giant Neutrino Ball


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