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.

2023 December 24
A nebula in purple and pink is shown with dust pillars 
curving around. In the centre is a bright orange spot.
Please see the explanation for more detailed information.

NGC 2440: Cocoon of a New White Dwarf
Image Credit: NASA, ESA, Hubble; Processing: H. Bond (STScI), R. Ciardullo (PSU), Forrest Hamilton (STScI)

Explanation: What's that in the centre? Like a butterfly, a white dwarf star begins its life by casting off a cocoon of gas that enclosed its former self. In this analogy, however, the Sun would be a caterpillar and the ejected shell of gas would become the prettiest cocoon of all. In the featured cocoon, the planetary nebula designated NGC 2440 contains one of the hottest white dwarf stars known. The white dwarf can be seen as the bright orange dot near the image centre. Our Sun will eventually become a white dwarf butterfly, but not for another 5 billion years.

Tomorrow's picture: mansion mountain moon


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