This artist concept depicts a quadruple-star system called HD 98800. The
system is approximately 10 million years old, and is located 150
light-years away in the constellation TW Hydrae.
HD 98800 contains four stars, which are paired off into doublets, or
binaries. The stars in the binary pairs orbit around each other, and the
two pairs also circle each other like choreographed ballerinas. One of the
stellar pairs, called HD 98800B, has a disk of dust around it, while the
other pair does not.
Although the four stars are gravitationally bound, the distance separating
the two binary pairs is about 50 astronomical units (AU) -- slightly more
than the average distance between our sun and Pluto.
Using NASA's Spitzer Space Telescope, scientists finally have a detailed
view of HD 98800B's potential planet-forming disk. Astronomers used the
telescope's infrared spectrometer to detect the presence of two belts in
the disk made of large dust grains. One belt sits approximately 5.9 AU
away from the central binary, or about the distance from the sun to
Jupiter, and is likely made up of asteroids and comets. The other belt
sits at 1.5 to 2 AU, comparable to the area where Mars and the asteroid
belt sit, and is made up of sand-sized dust grains.
