David S.F. Portree

Yesterday I wrote that the California & Carnegie Planet Search had announced on Monday that they found 28 new planets around other stars. It turns out that only five of the 28 are actual new discoveries. The Monday announcement was really a review of California & Carnegie Planet Search discoveries announced over the past year. (Thanks to Gerald Nordley for pointing this out.)

News media around the world made the same mistake (for example, here, here, and here). The California & Carnegie Planet Search press release on the Monday announcement seems to have generated the confusion.

The headlines should have read, “Team Announces Five New Planets.” Of course, if the news media knew that “only” five new planets had been found, we might not have seen any headlines.

I think that this goof is an indictment not only of press release writers and science reporters, but also of the way astronomers refer to the planets they find orbiting other stars. Few people can recognize the arcane alphanumeric designations they use. We need to start giving these worlds real names. If we did, these planets would become distinct, recognizable worlds, not mere interchangable sets of letters and numbers.

As I reported yesterday, the California & Carnegie team also found seven brown dwarfs - objects too massive to be planets but not massive enough to be a stars - and two objects that might be very light brown dwarfs or very heavy planets.

The 28 planets they discovered this past year probably resemble Jupiter: massive, stormy balls of gas and liquid. Some orbit their stars closer than Mercury orbits the Sun. Two orbit farther from their stars than does Jupiter. Five or six orbit their stars at about the distance Earth orbits the Sun. It’s possible that a large moon of a Jupiter-type planet orbiting a Sun-like star at about Earth’s distance could be habitable. Think Endor, the Ewok-infested moon in Episode VI of the Star Wars saga.