Volume 643, November 2020
|Number of page(s)||8|
|Section||Interstellar and circumstellar matter|
|Published online||18 November 2020|
Detailed 3D structure of Orion A in dust with Gaia DR2
Chalmers University of Technology, Department of Space, Earth and Environment,
2 Max Planck Institute for Astronomy (MPIA), Königstuhl 17, 69117 Heidelberg, Germany
Accepted: 28 September 2020
The unprecedented astrometry from Gaia’s second data release (DR2) provides us with an opportunity to study molecular clouds in the solar neighbourhood in detail. Extracting the wealth of information in these data remains a challenge, however. We have further improved our Gaussian-processes-based, three-dimensional dust mapping technique to allow us to study molecular clouds in more detail. These improvements include a significantly better scaling of the computational cost with the number of stars, and taking into account distance uncertainties to individual stars. Using Gaia DR2 astrometry together with the Two Micron All Sky Survey (2MASS) and the Wide-Field Infrared Survey Explorer (WISE) photometry for 30 000 stars, we infer the distribution of dust out to 600 pc in the direction of the Orion A molecular cloud. We identify a bubble-like structure in front of Orion A, centred at a distance of about 350 pc from the Sun. The main Orion A structure is visible at slightly larger distances, and we clearly see a tail extending over 100 pc that is curved and slightly inclined to the line of sight. The location of our foreground structure coincides with 5–10 Myr old stellar populations, suggesting a star formation episode that predates that of the Orion Nebula Cluster itself. We also identify the main structure of the Orion B molecular cloud, and in addition discover a background component to this at a distance of about 460 pc from the Sun. Finally, we associate our dust components at different distances with the plane-of-the-sky magnetic field orientation as mapped by Planck. This provides valuable information for modelling the magnetic field in three dimensions around star-forming regions.
Key words: ISM: clouds / ISM: bubbles / ISM: individual objects: Orion A / dust, extinction / ISM: magnetic fields
© S. Rezaei Kh. et al. 2020
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Open Access funding provided by Max Planck Society.
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