Astronomers find two similar-looking planets
An exoplanet doppelgänger has been discovered for the first time using direct imaging, but the pair's origins are very different
A newfound planet has been getting astronomers excited because it looks remarkably similar to one already well known. The recently discovered ‘twin’, 2MASS 0249 c, is the same size, brightness and has the same spectrum as beta Pictoris b.
The two planets have been discovered by direct imaging which, up until now, has always uncovered distinct objects. “Finding two exoplanets with almost identical appearances and yet having formed so differently opens a new window for understanding these objects,” says Michael Liu, an astronomer at the University of Hawaii and co-author of the new research.
To explain, 2MASS 0249 c orbits a couple of small, faint brown dwarfs some 2,000-times the distance of the Earth to the Sun. Since those dwarfs are not surrounded by a lot of gas or dust, the planet did not form by sucking gas from the star's disc, unlike gas giant beta Pictoris b. Instead, 2MASS 0249 c seems to have formed by directly accumulating gas from the original stellar nursery. It shows there are more ways than one to make exoplanets that look very similar.
“2MASS 0249 c looks like an underweight brown dwarf that formed from the collapse of a gas cloud,” says Kaitlin Kratter, astronomer at the University of Arizona. “They're both considered exoplanets, but 2MASS 0249 c illustrates that such a simple classification can obscure a complicated reality."