The world鈥檚 largest telescope array has caught our best ever glimpse of planets being born around a distant star. The image reveals that young stars can form planets much earlier than previously thought, which could have implications for how our own solar system developed.
In September, astronomers of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. The antennas can be moved across the desert to change how closely the array focuses in on a target. This reconfiguration involved moving them so that they were up to 15 kilometres apart, the furthest they have been, which enables them to make the crispest images yet in these wavelengths.
To test it out, the ALMA team pointed the dishes at HL Tauri, a star 450 light years away. 鈥淲ith this new capability of ALMA we are able to see at much higher resolution than before,鈥� says ALMA scientist Catherine Vlahakis.
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What they saw surprised them: although it is only a million years old, HL Tauri is already growing a family of planets. Planets are thought to develop when the dust and gas surrounding a star is spun into a disc, and gravity forces it into clumps. These clumps grow as they sweep up larger and larger particles to create planets, leaving behind gaps in the discs.
Simulations predicted that a star at HL Tauri鈥檚 relatively young age should host an unbroken disc, but ALMA has now seen a clear structure of concentric rings and gaps around the star 鈥� the first such observation. 鈥淚t was almost too good to be true,鈥� says Vlahakis. 鈥淲ith previous observations our best images looked like unresolved blobs.鈥�
ALMA鈥檚 image suggests planets can spring up more quickly than previously thought. This data can now be used to update simulations, giving us a clearer picture of our own past. 鈥淏y studying other systems such as this we can learn much more about the way in which our own solar system formed,鈥� says Vlahakis.
