There may come a day when exoplanet discoveries start to bore me, but we're not there yet. A day after the Kepler team announced the identification of Earth-sized planets orbiting a distant star, they're back with the description of a truly bizarre planetary system. In its past, KIC 05807616 expanded out to red giant size, swallowing two gas giants in the process. The cores of these planets continued to orbit, reemerging once the star shrunk again. Meanwhile, their impact on the star may have caused it to become an unusually hot form of dwarf star.

The star in question, KIC 05807616, has a rather interesting description: "a seemingly isolated pulsating hot B subdwarf." These have a somewhat unusual history. Normally, stars near the mass of our sun expand out as red giants, but then contract as they switch from fusing hydrogen to fusing the helium that has built up at their cores. Hot B dwarfs occur when something happens during the red giant phase that removes all the star's hydrogen, leaving nothing but a helium fusing core behind. KIC 05807616 has been in this stage for less than 20 million years, and in addition to its high temperatures, undergoes regular fluctuations, hence the "pulsating" part of that description.

Read the comments on this post