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 September 6
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.
Emerging Planetary Nebula CRL 618
Credit: Susan R. Trammell (UNC Charlotte) et al.,

Explanation: CRL 618 may look to some like an Olympian declaring victory. Only a few hundred years ago, however, CRL 618 appeared as a relatively modest red giant star. Since then it has run out of core material to fuse and so has started to become a planetary nebula. In its current proto-planetary nebula phase, CRL 618 is evolving quickly, expelling hot gasses in complex jets and rings moving outwards faster than 700,000 kilometers per hour. In a few thousand years, the glowing core of the cool red giant will be bare, revealing a hot white dwarf star. Much remains unknown about planetary nebulae formation, including details of how geometries like this form. Perhaps one day some part of this nebula will be able to declare victory - CRL 618 has an extraordinary abundance of carbon-chain molecules.

Tomorrow's picture: Stellar Spirograph

< | Archive | Index | Search | Calendar | Glossary | Education | About APOD | >

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/GSFC
& Michigan Tech. U.