Scientists are looking for Earth-like planets around other stars. But one way to limit the search can be to figure out where an Earth-like planet cannot exist and eliminate those types of systems.

In a new study, astronomers turned their attention to so-called hot Jupiters. These are Jupiter-sized planets that have an orbit of only about three days. The scientists looked at 63 hot Jupiters to see if they could find evidence for any nearby Earth-like planets. They found none.

But it could be that the companion planets are too small in size or mass or just aren’t detectable with the current techniques. So the researchers then turned to hot Neptunes, and warm Jupiters—these are Jupiters with slightly longer orbits. They found only 2 potential nearby planets among 222 hot Neptures. And of the 31 warm Jupiters, five showed evidence of a companion. The findings are in the Proceedings of the National Academy of Sciences. [Jason H. Steffen, Kepler constraints on planets near hot Jupiters]

The current theory is that hot Jupiters formed and then migrated in towards their stars. The researchers say that the migration might have “disrupted the formation of Earth-like planets.” Good thing our Jupiter kept its cool.

—Cynthia Graber

[The above text is an exact transcript of this podcast.]