Washington: A team of astronomers has obtained proof of formation of a giant planetary system around a young star by the observations with the Atacama Large Millimeter/submillimeter Array (ALMA).
The research team, led by astronomers at Osaka University and Ibaraki University, observed a young star named HD 142527 in the constellation Lupus (the Wolf) with ALMA.
The ALMA image shows that cosmic dust, which is component material of planets, is circling around the star in a form of asymmetric ring.
By measuring the density of dust in the densest part of the ring, the astronomers found that it is highly possible that planets are now being formed in that region. This region is far from the central star, about 5 times larger than the distance between the Sun and the Neptune.
The research team plans further observations of HD 142527 with ALMA for closer investigation, as well as other protoplanetary disks to have a comprehensive understanding of the planet formation in general.
A baby star is surrounded by a ring of dust (*1) and gas, which would be the component material of planets. Recent near-infrared (*2) observations with the NAOJ Subaru Telescope revealed that protoplanetary disks have structures that are far more complex than we expected. Spiral or gap structures are thought to be associated with hidden planets in the disk (*3).
However, it is impossible to measure the amount of dust and gas in the densest part of the disk by near-infrared observations. Since near-infrared light is easily absorbed or scattered by a large amount of dust, it isn`t suitable for observing the innermost part of the dense region of the disk. Then, the key to the solution will be millimeter and submillimeter wave (*4), which can be observed with ALMA. Millimeter/submillimeter wave has longer wavelength than near-infrared light and is poorly absorbed by dust, which enables astronomers to peer into the inner part of the disk. Low spatial resolution was a weak point in millimeter/submillimeter observations, but it is now greatly improved by ALMA.