Huge jets of water found streaming from distant protostar


Radio-telescopes in Chile push the limit for terrestrial observations. Ben Lewis reports.


The Cat's Paw Nebula.
The Cat's Paw Nebula.
George Varouhakis / NASA

Astronomers have spotted incredible jets of water vapour streaming away from a protostar in the Cat's Paw Nebula, a star-forming region located about 5500 light-years from Earth.

The observations, published in The Astrophysical Journal Letters, were made by a group from the National Radio Astronomy Observatory in Virginia in the United States, using the Atacama Large Millimetre Array (ALMA), a collection of radio telescopes in Chile, owned by the European Southern Observatory (ESO).

Led by the observatory’s Geoffrey Blake, the detected submillimeter-wavelength light emitted by jets of heavy water streaming away from the protostar located in the Cat’s Paw Nebula, known formally as NGC 6334I.

Heavy water contains the hydrogen isotope deuterium, instead of hydrogen itself. A product of the Big Bang, there are about 26 deuterium atoms for every million hydrogen atoms across the universe.

The jets are a result of star formation. As a star begin to coalesce out of massive clouds of dust and gas, most of the material surrounding it is pulled towards the mass at the centre. However, some is propelled away from the growing protostar as a pair of jets.

The heavy water the researchers observed is flowing away from either a single protostar or a small cluster of them. The jets are likely to have formed relatively recently, because they are smaller and orientated differently to potentially more-mature jets seen in the same region.

McGuire and colleagues also note that the ALMA’s sister telescope, the Very Large Array, detected low frequency masers – naturally occurring microwave versions of lasers – where the water jets slam into surrounding gas.

On a night of perfect atmospheric conditions, the astronomers pushed ALMA’s equipment to detect the highest frequency signals possible, wavelengths of 0.3 to 0.4 millimetres.

“Normally, we wouldn't be able to directly see this particular signal at all from the ground,” says co-author Crystal Brogan.

“However, ALMA can in fact detect that signal. This is something no other telescope on Earth can achieve.”

  1. http://iopscience.iop.org/article/10.3847/2041-8213/aad7bb/meta
  2. https://www.eso.org/public/
  3. http://www.constellation-guide.com/cats-paw-nebula/
  4. http://www.sciencemag.org/news/2014/09/half-earths-water-formed-sun-was-born
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