3D shape of Orion A with Gaia DR2

Author(s)
Josefa E. Großschedl, João Alves, Stefan Meingast, Birgit Hasenberger
Abstract

The giant molecular cloud Orion A is the closest massive star-forming region to earth (d ∼400 pc). It contains the rich Orion Nebula Cluster (ONC) in the North, and low-mass star-forming regions (L1641, L1647) to the South. To get a better understanding of the differences in star formation activity, we perform an analysis of the gas mass distribution and star formation rate across the cloud. We find that the gas is roughly uniformly distributed, while, oddly, the ONC region produced about a factor of ten more stars compared to the rest of the cloud. For a better interpretation of this phenomenon, we use Gaia DR2 parallaxes, to analyse distances of young stellar objects, using them as proxy for cloud distances. We find that the ONC region indeed lies at about 400 pc while the low-mass star-forming parts are inclined about 70

° from the plane of the sky reaching until ∼70 pc. With this we estimate that Orion A is an about 90 pc long filamentary cloud (about twice as long as previously assumed), with its "Head" (the ONC region) being "bent" and oriented towards the galactic mid-plane. This striking new view allows us to perform a more robust analysis of this important star-forming region in the future.

Organisation(s)
Department of Astrophysics
Journal
Proceedings of the International Astronomical Union
Volume
14
Pages
27-33
No. of pages
7
ISSN
1743-9213
DOI
https://doi.org/10.1017/S1743921319001492
Publication date
12-2018
Peer reviewed
Yes
Austrian Fields of Science 2012
103003 Astronomy, 103004 Astrophysics
Keywords
ASJC Scopus subject areas
Astronomy and Astrophysics, Space and Planetary Science
Portal url
https://ucris.univie.ac.at/portal/en/publications/3d-shape-of-orion-a-with-gaia-dr2(d192aa82-bd33-439b-b51c-756a3183a958).html