* Astronomy

Members Login
Post Info TOPIC: NGC7023


Posts: 131433

Title: The 15 - 20 Micron Spitzer Spectra of Interstellar Emission Features in NGC 7023
Authors: K. Sellgren (Ohio State), K. I. Uchida (JPL), M. W. Werner (JPL)

We present 15 - 20 micron long-slit spectra, from the Infrared Spectrograph (IRS) on Spitzer, of NGC 7023. We observe recently-discovered interstellar emission features, at 15.9, 16.4, 17.0, 17.4, 17.8, and 18.9 microns, throughout the reflection nebula. The 16.4 micron emission feature peaks near the photodissociation front northwest of the star, as do the aromatic emission features (AEFs) at 3.3, 6.2 and 11.3 microns. The 16.4 micron emission feature is thus likely related to the AEFs and radiates by non-equilibrium emission. The new 18.9 micron emission feature, by contrast, decreases monotonically with stellar distance. We consider candidate species for the 18.9 micron feature, including polycyclic aromatic hydrocarbons, fullerenes, and diamonds. We describe future laboratory and observational research needed to identify the 18.9 micron feature carrier.

Read more (674kb, PDF)

Page 1 of 1  sorted by
Quick Reply

Please log in to post quick replies.

Create your own FREE Forum
Report Abuse
Powered by ActiveBoard