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 3, 1999
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.

Methane Dwarf
Credit: SDSS Collaboration

Explanation: While hunting through Sloan Sky Survey data in search of distant quasars, Princeton astronomers Xiaohui Fan and Michael Strauss came upon an undiscovered type of object very nearby - now dubbed a methane dwarf. Marked by white lines in this recently released image, the isolated, faint, but extremely red methane dwarf lies only 30 or so light-years away in the constellation Ophiuchus. Intermediate in size between a star and a planet, it is thought to be about 10 to 70 times as massive as Jupiter. The moniker "methane dwarf" was derived from the strong signature of methane gas in the object's spectrum. Along with the red color, the presence of methane (CH4) indicates that this object is cool - cooler than brown dwarfs which lack the strong methane signature yet are the only other known objects in this mass range. Subsequent observations have now raised the total to three detected methane dwarfs, but because they are so difficult to find so far no one knows if they are rare or common in our Galaxy.

Tomorrow's picture: NGC 3603

< 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.