Letter to the Editor

The complexity of Orion: an ALMA view

III. The explosion impact^⋆

¹ LERMA & UMR8112 du CNRS, Observatoire de Paris, PSL University, Sorbonne Universités, CNRS, 75014 Paris, France
e-mail: laurent.pagani@obspm.fr
² Department of Astronomy, University of Michigan, 311 West Hall, 1085 S. University Ave, Ann Arbor, MI 48109, USA
³ JPL, Pasadena, CA, USA
⁴ Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA
⁵ Department of Astronomy, University of Massachusetts, Amherst, MA 01003, USA
⁶ Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France

Received: 14 February 2019
Accepted: 16 March 2019

Abstract

The chemistry of complex organic molecules in interstellar dark clouds is still highly uncertain in part because of the lack of constraining observations. Orion is the closest massive star-forming region, and observations making use of ALMA allow us to separate the emission regions of various complex organic molecules (COMs) in both velocity and space. Orion also benefits from an exceptional situation, in that it is the site of a powerful explosive event that occurred ∼550 years ago. We show that the closely surrounding Kleinmann-Low region has clearly been influenced by this explosion; some molecular species have been pushed away from the densest parts while others have remained in close proximity. This dynamical segregation reveals the time dependence of the chemistry and, therefore allows us to better constrain the formation sequence of COMs and other species, including deuterated molecules.