Planets are formed when the swirling dust and gas that circles young stars coalesces into solid bodies. For the first time, astronomers have found what they believe is a planet in the process of formation.
The star T Chamaeleontis (T Cha) is a very young star (seven million years old) located about 350 light years from Earth. Like many young stars, it is surrounded by a ring of dust. However, astronomers led by Johan Olofsson of the Max Planck Institute were able to discern a gap in that disk. They used an instrument called the Very Large Telescope (VLT) Interferometer to observe that the star was encircled by dust at a distance of about 20 million kilometers, and again at about 1.1 billion kilometers. The space between those two rings was largely devoid of dust.
There are a number of mechanisms that can account for the dissipation of dust around a star, including planet formation. Nuria Huélamo of Centro de Astrobiología and a team of astronomers used another instrument on the VLT to find such a planet. The candidate object was located about a billion kilometers from T Cha, near the outer edge of the dust gap. The scientists aren’t sure yet whether the object will turn out to be a brown dwarf surrounded by dust or a planet.
In any case, this is the first example of an object in the process of clearing a path around a star by accreting all the dust and gas within that region.
Caption: This artist’s impression shows the disc around the young star T Cha. Using ESO’s Very Large Telescope this disc has been found to be in two parts, a narrow ring close to the star and the remainder of the disc material much further out. A companion object, seen in the foreground, has been detected in the gap in the disc that may be either a brown dwarf or a large planet. The inner dust disc is lost in the glare of the star on this picture.
Credit: ESO/L. Calçada