7th November 2014
The clearest ever image of planets forming around a young star
The birth of planets has been revealed in astonishing detail by a telescope with 10 times the resolution of Hubble.
The Atacama Large Millimetre Array (ALMA) is a new radio telescope in northern Chile that became fully operational in 2013. Costing $1.4 billion, it is the most expensive ground-based telescope in the world, and the most sensitive at millimetre and submillimetre wavelengths. A cluster of 66 high-precision antennas work in unison to achieve phenomenal resolution.
ALMA was designed to open an entirely new "window" on the universe. Its capabilities have been demonstrated once again with a stunning image released by astronomers this week, showing extraordinarily fine detail in the planet-forming disk around a young star. These new results are a major step forward in the understanding of protoplanetary disks and the formation of planets.
HL Tau is a million-year-old Sun-like star, located 450 light-years from Earth in the constellation of Taurus. The photo seen here exceeds all expectations and reveals a series of concentric and bright rings, separated by gaps. These new substructures have never been seen before and are believed to show the possible positions of planets forming in the dark patches – similar to how our own Solar System would have looked more than 4 billion years ago.
ALMA Deputy Director, Stuart Corder: "These features are almost certainly the result of young planet-like bodies forming in the disk. This is surprising, since such young stars are not expected to have large planetary bodies capable of producing the structures we see in this image."
Catherine Vlahakis, Deputy Program Scientist: "When we first saw this image, we were astounded at the spectacular level of detail. HL Tauri is no more than a million years old, yet already its disk appears to be full of forming planets. This one image alone will revolutionise theories of planet formation."
ALMA's new high-resolution capabilities were achieved by spacing the antennas up to 15 kilometres apart. This baseline at millimetre wavelengths enabled a resolution of 35 milliarcseconds – equivalent to a penny seen from over 110 kilometres away. An even larger cluster of telescopes known as the Square Kilometre Array is planned for operation in 2024. This will have 50 times the resolution of ALMA and 500 times that of Hubble.