3D shape of Orion A from Gaia DR2

Author(s)
Josefa E. Großschedl, João Alves, Stefan Meingast, Christine Ackerl, Joana Ascenso, Hervé Bouy, Andreas Burkert, Jan Forbrich, Verena Fürnkranz, Alyssa Goodman, Alvaro Hacar Gonzalez, Gabor Herbst-Kiss, Charles J. Lada, Irati Larreina, Kieran Leschinski, Marco Lombardi, André Moitinho, Daniel Mortimer, Eleonora Zari
Abstract

We use the Gaia DR2 distances of about 700 mid-infrared selected young stellar objects in the benchmark giant molecular cloud Orion A to infer its 3D shape and orientation. We find that Orion A is not the fairly straight filamentary cloud that we see in (2D) projection, but instead acometary-like cloud oriented toward the Galactic plane, with two distinct components: a denser and enhanced star-forming (bent) Head, and a lower density and star-formation quieter ˜75 pc long Tail. The true extent of Orion A is not the projected ˜40 pc but ˜90pc, making it by far the largest molecular cloud in the local neighborhood. Its aspect ratio (˜30:1) and high column-density fraction (˜45%) make it similar to large-scale Milky Way filaments ("bones"), despite its distance to the galactic mid-plane being an orderof magnitude larger than typically found for these structures. Full Table B.1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(ftp//130.79.128.5) or via cdsarc.u-strasbg.fr/viz-bin/qcat

Organisation(s)
Department of Astrophysics, Research Network Data Science
External organisation(s)
Universidade do Porto, Université Bordeaux Montaigne, Ludwig-Maximilians-Universität München, Max-Planck-Institut für extraterrestrische Physik, University of Hertfordshire, Harvard-Smithsonian Center for Astrophysics, Universitá degli Studi di Milano, Universidade de Lisboa, University of Cambridge, Leiden Observatory, Leiden University
Journal
Astronomy & Astrophysics
Volume
619
No. of pages
9
ISSN
0004-6361
DOI
https://doi.org/10.1051/0004-6361/201833901
Publication date
11-2018
Peer reviewed
Yes
Austrian Fields of Science 2012
103003 Astronomy, 103004 Astrophysics
Keywords
Portal url
https://ucris.univie.ac.at/portal/en/publications/3d-shape-of-orion-a-from-gaia-dr2(d1c9963e-234a-4d00-a41c-bd886178daff).html