ALMA telescope finds powerful emissions of carbon monoxide from a young star

An international team of astrophysicists led by Osaka Metropolitan University and Kyushu University

studied young stars in the Lesser MagellanicCloud using the ALMA telescope. In a study published in The Astrophysical Journal Letters, scientists report the first detection of a bipolar outflow in a young star with low metallicity, containing elements heavier than hydrogen and helium.

Bipolar outflow is two continuous streamsgas ejected from the poles of the star. Such a process has been found in many protostellar systems. But all observations concerned only stars with a high content of heavy elements - with a metallicity comparable to that of the Sun and higher.

Bipolar outflow from the young star Y246. The location of the star is marked with a cross. Image: Osaka Metropolitan University

In a new study, the authors observed bipolarthe outflow of carbon monoxide (CO) from the poles of the young star Y246 with a metallicity 5 times less than the solar one. An analysis of data from the Atakama Large Millimeter (Submillimeter) Array (ALMA) showed that gas is ejected from the poles of this star at a speed of 54,000 km/h in both directions. These observations are in full agreement with the models built for stars with a large number of heavy elements.

Heavy elements in interstellar mattersignificantly affect the mechanism of star formation. In the early Universe, the content of heavy elements was lower than in the modern one. The Small Magellanic Cloud, one of the closest galaxies to Earth, is characterized by a low abundance of elements heavier than helium. The metallicity of the stars in it is comparable to the similar parameter for galaxies that existed about 10 billion years ago.

Emission of carbon monoxide (CO) with blue and red shifts. Image: Kazuki Tokuda et al., The Astrophysical Journal Letters

The researchers believe that the bipolar outflowin modern systems slows the rotation of young stars and accelerates their growth. The discovery of a similar mechanism in a young star with low metallicity shows that similar effects were common in the early universe.

Cover: Small Magellanic Cloud. Image: ESO/VISTA VMC

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