Scientist capture 'sharpest ever' image of planets forming around a star

The star - HL Tauri - is 450 light years away from Earth

ALMA image of the protoplanetary disc around HL Tauri (ALMA (ESO/NAOJ/NRAO))

Scientist have captured the clearest ever image of planets forming around a young star.|

In the centre is the star HL Tau - less than a million years old and not dissimilar in composition to our own Sun – surrounded by fiery concentric circles of dust and gas.

The gaps in this glowing disc make it look like the cross-section of some cosmic tree, but each dark ring shows the future orbit of a planet - their coalescing bodies sweeping a clear path through the debris.

The image was captured by an array of radio telescopes in the Atacama desert in northern Chile known as ALMA (the Atacama Large Millimeter/submillimeter Array). Scientists say it’s a massive step forward in our knowledge about the genesis of planets.

HL Tauri on the left and our own Solar System on the right. HL Tauri's disc is three times wider than Neptune's orbit. Image: ALMA

“When we first saw this image we were astounded at the spectacular level of detail,” said ALMA deputy program scientist Catherine Vlahakis. “HL Tauri is no more than a million years old, yet already its disc appears to be full of forming planets.”

Tim de Zeeuw, director general of the European Southern Observatory (ESO) added that such a high resolution image would help us understand also the formation of Earth more than four billion years ago.

“Most of what we know about planet formation today is based on theory,” said de Zeeuw in a press release. “Images with this level of detail have up to now been relegated to computer simulations or artist’s impressions.”

An artist's impression of planetary genesis around a young star like HL Tauri.

Star formation itself happens in massive interstellar clouds of gas and fine dust, which collapse in random patterns to form denser clumps which begin to rotate and eventually form stars.

These begin life surrounding by the ‘accretion discs’ seen above, with gravity causing material to spiral inward and feed the growth of the star while localized clumps within the surrounding matter eventually become planets, comets and asteroids.