The Structure of NGC 7027 and a Determination of Its Distance by Measurement of Proper Motions
Abstract
Radio observations of the PN NGC 7027, obtained at 4.885 and 14.965 GHz (resolution 0.35 arcsec) using the B configuration of the VLA in 12-h runs during August 1982, May 1985, and September 1986, are reported. The data-reduction procedures are outlined, and the results are presented in tables, graphs, and contour maps. Extreme limb brightening is observed and attributed to inverse-square dilution of ionizing radiation from the central star. Comparison of the maps from three epochs reveals steady expansion and implies a distance of 880 + or - 150 pc.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 1989
- DOI:
- 10.1086/167011
- Bibcode:
- 1989ApJ...336..294M
- Keywords:
-
- Planetary Nebulae;
- Stellar Evolution;
- Stellar Luminosity;
- Astronomical Maps;
- Astronomical Models;
- Brightness Distribution;
- Ionized Gases;
- Very Large Array (Vla);
- Astrophysics;
- NEBULAE: INDIVIDUAL NGC NUMBER: NGC 7027;
- NEBULAE: INTERNAL MOTIONS;
- NEBULAE: PLANETARY