From ScienceDaily, astronomers have discovered a very odd object orbiting a brown dwarf known as 2M1207A. The object, known as 2M1207B (those astronomers are awfully clever with those names, aren't they?) is about the size of Saturn, but many of its charateristics do not match up. The system itself is very young, around 8 million years old, but the planet is far too warm, at 2400 degrees F, than it should be.
Conversely, given that temperature, it should be up to 10 times more bright than observations show it to be. The only hypothesis that answers the contradiction is that the object has suffered a cosmic collision in the recent past. If true, it would be the first such recently collided object we have ever observed.
"The planets in our solar system assembled from dust, rock, and gas, gradually growing larger over millions of years. But sometimes, two planet-sized objects collided catastrophically. For example, the Moon formed when an object about half the size of Mars hit the proto-Earth. If planet formation works the same way in other star systems, then 2M1207B might be the product of a collision between a Saturn-sized gas giant and a planet about three times the size of Earth. The two smacked into each other and stuck, forming one larger world still boiling from the heat generated in the collision."
Observations on the object will continue which could confirm the theory, including a surface gravity calculation from a spectrum analysis, which could give us the answer within a year or so. Even if 2M1207B's odd characteristics are not the result of a collision, astronomers believe we will discover many such objects with the next generation of space and Earth based telescopes being planned or built.