ESA astronomers announced this week that they’ve discovered two more exoplanets, or planets outside our solar system, using the space-based COROT observatory. The two new finds are Jupiter-sized gas giants that orbit close to their parent stars.

But the astronomers also reported that COROT has picked up another object that they can’t quite explain. This space oddity, COROT-exo-3b, looks to lie somewhere between a brown dwarf and a planet. It may even be a star, though if that’s the case, scientists say it would be among the smallest ever detected.

The observatory is designed to pick up small, rocky planets, so the two new Jupiter-sized finds aren’t even its specialty. But the scientists say that they’re also hoping to re-examine a fourth object, a potential exoplanet that may be Earth-scale.