A new detailed map of the Orion A molecular cloud

Orion A (Image courtesy NSF/S. Kong, J. Feddersen, H. Arce & CARMA-NRO Orion Survey team)
Orion A (Image courtesy NSF/S. Kong, J. Feddersen, H. Arce & CARMA-NRO Orion Survey team)

An article published in the journal “The Astrophysical Journal Supplement Series” describes the results of the CARMA-NRO Orion Survey, a high-resolution mapping of the molecular cloud called Orion A, one of the two giant molecular clouds in the Orion molecular cloud complex. A team of astronomers combined the observations of the CARMA and NRO radio telescopes to map the stars but also the gas movements inside the cloud.

The molecular cloud known as Orion A is the one that appears from Earth near the part of the constellation of Orion known as the sword. “Only” 1,350 light years away from the Earth, it’s the region of intense star formation closest to the Earth where both very massive and smaller – with a mass similar to the Sun’s – stars form. That’s why the whole Orion complex is the subject of several studies and for example at the beginning of 2017 an article published in the journal “Astronomy & Astrophysics” described the view of the cloud generated by the VISION survey.

The CARMA-NRO Orion Survey is based on observations of two radio telescopes, the Combined Array for Research interferometer in Millimeter-wave Astronomy (CARMA), which ceased operations in 2015 and consisted of an array of 23 antennas, and the Nobeyama Radio Observatory (NRO) single 45-meter antenna. The Yale Center for Research Computing participated in the research by handling the big datasets collected and producing the images.

The combination of the two radio telescopes’ different features allowed to combine the details captured by CARMA with the wide-angle of NRO to obtain the details of individual stars in formation and the overall shape and motions of the Orion A molecular cloud. Shuo Kong of Yale, the first author of the study, explained that the maps created explore a wide range of physical scales needed to study how stars form in molecular clouds and how young stars influence the cloud in which they form.

The birth and evolution of stars are the subject of a lot of research both theoretical and observation-based because the answers are helping to better understand the mechanisms that led to the birth of the Sun and therefore of the Earth. However, in the case of stars much more massive than the Sun the maps show how the energy released in the surrounding area has a major impact on it.

This research can also be useful to create star formation models for other galaxies. That’s because this type of investigation allows to improve our knowledge of the birth and evolution of the stars thanks to the relative proximity of the Orion A cloud and the results can be applied to clouds millions of light years away in which it’s not possible to detect all the details.

In essence this type of investigation creates a database of information that can subsequently be used in other very diverse research. In some cases it will be more specific studies of single stars in the Orion A cloud, among which the CARMA-NRO Orion Survey will help to find the most interesting ones.

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