Next Article in Journal
Minimum Length Uncertainty Relations in the Presence of Dark Energy
Previous Article in Journal
Monitoring the Extragalactic High Energy Sky
Previous Article in Special Issue
Radio Continuum Spectra of Planetary Nebulae
Article Menu

Export Article

Open AccessArticle
Galaxies 2019, 7(1), 10; https://doi.org/10.3390/galaxies7010010

Understanding the Spatial Distributions of the Ionic/Atomic/Molecular/Dust Components in PNe

1
Department of Physics & Astronomy, University of Denver, 2112 E. Wesley Ave., Denver, CO 80208, USA
2
Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan
Current address: Okayama Observatory, Kyoto University, Honjo, Kamogata, Asakuchi, Okayama 719-0232, Japan.
*
Author to whom correspondence should be addressed.
Received: 4 December 2018 / Revised: 28 December 2018 / Accepted: 29 December 2018 / Published: 4 January 2019
(This article belongs to the Special Issue Asymmetric Planetary Nebulae VII)
Full-Text   |   PDF [415 KB, uploaded 7 January 2019]   |  

Abstract

Planetary nebulae (PNe) are often recognized as the hallmark of compact H ii regions in the Universe. However, there exist dusty neutral regions extending beyond the central ionized region. We demonstrate that such dusty neutral regions (also known as photo-dissociation regions, or PDRs) around the central ionized region are significant parts of PNe in terms of energetics and mass. We do so by using our latest dusty photoionization model of NGC 6781 (of 13 parameters) based on one of the most comprehensive panchromatic data sets ever assembled for a PN encompassing from X-ray to radio (of 136 constraining data, including 19 flux densities, 78 line fluxes, and 37 band fluxes). We find that NGC 6781, evolved out of a 2.25–3.0 M star located 460 pc away from us, possesses a massive concentration of neutral gas (molecular hydrogen) just beyond the central ionized region and that the amount of ionized gas in NGC 6781 is only 22% of the observationally accounted amount of matter in the circumstellar environment, which itself does not even account for the amount of mass presumably ejected by the central star during the last thermal pulse event according to the latest evolutionary models. This means that the observed nebula in this PN is only the tip of the iceberg. View Full-Text
Keywords: dust; extinction; ISM: abundances; planetary nebulae: individual (NGC 6781) dust; extinction; ISM: abundances; planetary nebulae: individual (NGC 6781)
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Ueta, T.; Otsuka, M.; The HerPlaNS consortium. Understanding the Spatial Distributions of the Ionic/Atomic/Molecular/Dust Components in PNe. Galaxies 2019, 7, 10.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Galaxies EISSN 2075-4434 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top