Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· arXiv e-print (arXiv:0810.4375)
· On-line Data
· References in the article
· Citations to the Article (2) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (48)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
The Three-Dimensional Dynamic Structure of the Inner Orion Nebula
Authors:
O'Dell, C. R.; Henney, W. J.; Abel, N. P.; Ferland, G. J.; Arthur, S. J.
Affiliation:
AA(Department of Physics and Astronomy, Vanderbilt University, Box 1807-B, Nashville, TN 37235, USA ), AB(Centro de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Apartado Postal 3-72, 58090 Morelia, Michaoacán, Mexico ), AC(Department of Mathematics and Physics, College of Applied Science, University of Cincinnati, Cincinnati, OH 45221, USA ), AD(Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506, USA), AE(Centro de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Apartado Postal 3-72, 58090 Morelia, Michaoacán, Mexico )
Publication:
The Astronomical Journal, Volume 137, Issue 1, pp. 367-382 (2009). (AJ Homepage)
Publication Date:
01/2009
Origin:
IOP
AJ Keywords:
H II regions, ISM: individual: Orion Nebula NGC 1976, stars: formation
DOI:
10.1088/0004-6256/137/1/367
Bibliographic Code:
2009AJ....137..367O

Abstract

The three-dimensional structure of the brightest part of the Orion Nebula is assessed in the light of published and newly established data. We find that the widely accepted model of a concave blister of ionized material needs to be altered in the southwest direction from the Trapezium, where we find that the Orion-S feature is a separate cloud of very optically thick molecules within the body of ionized gas, which is probably the location of the multiple embedded sources that produce the optical and molecular outflows that define the Orion-S star formation region. Evidence for this cloud comes from the presence of H2CO lines in absorption in the radio continuum and discrepancies in the extinction derived from radio-optical and optical-only emission. We present an equilibrium Cloudy model of the Orion-S Cloud, which successfully reproduces many observed properties of this feature, including the presence of gas-phase H2CO in absorption. We also report the discovery of an open-sided shell of [O III] surrounding the Trapezium stars, revealed through emission-line ratio images and the onset of radiation shadows beyond some proplyds. We show that the observed properties of the shell are consistent with it being a stationary structure, produced by shock interactions between the ambient nebular gas and the high-velocity wind from θ1 Ori C. We examine the implications of the recently published evidence for a large blueshifted velocity of θ1 Ori C with respect to the Orion molecular cloud, which could mean that this star has only recently begun to photoionize the Orion Nebula. We show that current observations of the nebula do not rule out such a possibility, so long as the ionization front has propagated into a pre-existing low-density region. In addition, a young age for the nebula would help explain the presence of nearby proplyds with a short mass-loss timescale to photoablation.

Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA Contract No. NAS 5-26555.

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints