Density of the column of dust and magnetic fields towards the Orion clouds. Credit: Rezaeikhoshbakht et al., 2020.
Using a three-dimensional mapping technique, astronomers in Sweden and Germany have explored a nearby molecular cloud known as Orion A. The new study reveals more details about the structure and nature of this cloud. The research was featured in an article published July 6 in the arXiv prepress repository.
Located 1,000 to 1,400 light years away, the Orion Molecular Cloud Complex (Orion Complex for short) is a star-forming region spanning hundreds of light-years across. It is one of the most active regions of nearby star formation visible in the night sky and consists of two giant molecular clouds called Orion A and Orion B.
Around 3,000 young star objects have formed in Orion A in the past million years, making it the most active star-forming region in the local neighborhood. However, although this molecular cloud has been extensively studied in the past, its complex structure is still not fully understood.
One of the methods that could help investigate the structure of molecular clouds is to map their entire three-dimensional dust distribution. Knowing the three-dimensional distribution of dust to the Orion Complex can provide valuable information about the distance and structure of its clouds. So, a team of astronomers led by Sara Rezaeikhoshbakht from Chalmers University of Technology in Gothenburg, Sweden used this technique to explore the structure of Orion A.
“In this paper, we improved our mapping technique by including distance and extinction uncertainties, along with solving computational constraints, allowing us to exploit a large data set such as Gaia DR2 as input, and produce detailed three-dimensional dust Orion A map, “the researchers wrote in the article.
The team analyzed the data set from ESA’s Gaia satellite (Data Release 2, DR2) to obtain the three-dimensional positions of the stars. The study was completed with data from NASA’s WISE spacecraft and the All-Sky Two-Micron Survey (2MASS).
The method allowed astronomers to illustrate the entire shape of Orion A with its tail extended at distances of approximately 1,600 light years. The results suggest that the cloud length exceeds 300 light years.
The study reports, for the first time, a bubble-like dust over-density at approximately 1,150 light-years from Earth against the Orion A cloud. In addition, a background component of the Orion B cloud was identified at a distance of about 1,500 light years.
Furthermore, astronomers found the presence of stellar associations older than that of the Orion Nebula Group (ONC), a very young group (less than 1 million years old) in Orion A. These associations were identified in the same location as the Close-up detected dust overload, and researchers assume it indicates an early episode of star formation in front of ONC.
“This could have triggered subsequent episodes of star formation in the region,” the scientists explained.
Detailed three-dimensional structure of OrionA powder with Gaia DR2, arXiv: 2007.01331 [astro-ph.GA] arxiv.org/abs/2007.01331
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Citation: Orion A molecular cloud structure investigated in detail (2020, July 13) retrieved on July 13, 2020 from https://phys.org/news/2020-07-molecular-cloud-orion.html
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