News

Planetary Picture? Criteria for planethood cloud object's identity

By
10:16am, May 4, 2005

When is a Jupiterlike object a planet and when is it just a blob of gas? That's the question that astronomers are debating this week after two teams independently confirmed that a distant speck of light recorded a year ago is the first image of a planetary-size body beyond the solar system.

Two to five times as massive as Jupiter, the body would seem to automatically qualify as a giant planet. But the object almost certainly doesn't meet what many astronomers consider to be an equally important criterion for planethood: formation from a swirling disk of gas and dust that surrounds a young star.

This article is available only to subscribing members. Join SSP today or Log in.

More from this issue of Science News

[title_1]