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 9, 1999
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.

WR 104: Pinwheel Star
Credit: U.C. Berkeley Space Sciences Laboratory, W.M. Keck Observatory

Explanation: Like a cosmic lawn sprinkler, dust streaming from a rotating star system creates a pinwheel pattern in this false color infrared image. Astronomers discovered the surprising star dust scenario using a sophisticated interferometer and the 10 meter Keck I telescope to observe the bright Wolf-Rayet star WR 104. Wolf-Rayet stars are thought to be massive objects on the brink of a cataclysmic supernova explosion - having grown so hot and bright that their intense light begins to drive material away in a stellar wind. The problem is, their starlight would also be so intense that any dust flakes should be destroyed! A possible solution to this dusty dilemma is that a companion star exists hidden in the bright central region, generating wind interactions which shield a relatively narrow dust forming region from the light of WR 104. As the binary system rotates, the spray of surviving dust particles appears to spiral outward.

Tomorrow's picture: Hunter, Dog, Bull, Canary

< 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.