Harvard Scientists Find Solar System

Astronomers from the Harvard-Smithsonian Center for Astrophysics (CFA), in conjunction with three other research institutions, have discovered an entire solar system orbiting the star Upsilon Andromedae.

The system, which consists of three planets comparable in size to Jupiter, was the first of its kind to be discovered, according to a report released yesterday by San Francisco State University, whose scientists identified the system independent of the Harvard team.

The High-Altitude Observatory in Boulder, Colo., also collaborated with Harvard in the research.

Although scientists have found individual planets orbiting other stars, this was the first time a star was found with multiple planets, said Peter Nisenson, a member of the team at Harvard that made the discovery.

Nisenson, who is also an associate at the Harvard College Observatory, said planets are too small for scientists to see using current technology.

Instead, they must infer their existence by examining the "wobbling" in nearby stars caused by the gravitational pull of the planet.

Unfortunately, this method of detection has its drawbacks. It is only sensitive enough to detect planets of massive size that are also in close proximity to a star.

Such planets, however, are unlikely to exist, as large planets typically form some distance from their sun.

"[The fact that so many have been found] suggests that planets themselves are quite prevalent," Nisenson said.

The first planet orbiting Upsilon Andromedae was discovered in 1996 by researchers at San Francisco State University. But researchers noticed an irregularity to their results, suggesting that their explanation of the star's "wobbling" was incomplete.

"It became clear that there was another component of the system that could only be discovered by examining long-term trends in the data," Nisenson said.

Nisenson also pointed out that two of the discovered planets were within "the habitable zone," the distance from a star that corresponds to planets with temperatures roughly similar to those of Venus, Earth and Mars.

"There's no reason not to think that these planets might have moons that might have life on them," Nisenson said.