A graduate student's discovery that a nebulous cloud of dust several trillion miles wide is shaped like a disk may give scientists clues as to how the earth was formed.

While doing thesis research in Chile this March, Ray Jayawardhana, a student in the department of astrophysics and a resident tutor in Quincy House, observed that a dust ring around the star astronomers refer to as HR 4796A was shaped like a disk, which may indicate the presence of planets.

"It is a snapshot of a young solar system in the making," Jayawardhana said. "It is a missing link between disks around Younger stars and disks around older stars."

Dr. Lee Hartmann, a senior astrophysicist at the Harvard-Smithsonian Center for Astrophysics, said the hole in the center of the disk "is about the size of a planetary system" which suggests that the disk is the early stage of a solar system. The presence of planets, however, is not in any way confirmed. "We have not detected any planets directly or indirectly," Jayawardhana said.

Hartmann said he does not think the presence of planets will be detected any time soon.

"I think for a long time the evidence is going to have to be indirect," Hartmann said. "One possibility is that the planets might cause ripples in the disk because of their gravity."

According to Hartmann, HR 4796A, a star about 20 times more luminous than the Sun, is "about 8 to 10 million years old" which he said is around the age at which planets are estimated to form.

Jayawardhana made the discovery at roughly the same time as a team from NASA's Jet Propulsion Laboratory in California and Franklin & Marshall College in Lancaster, Pa.

Jayawardhana's discovery was made using a mid-infrared camera recently developed at the University of Florida.

Hartmann and Jayawardhana are also collaborating with astronomy lecturer Giovanni G. Fazio.