NGC 6884
Planetary nebula in the constellation of Cygnus
From Wikipedia, the free encyclopedia
NGC 6884 is a planetary nebula[4] located in the constellation Cygnus, less than a degree to the southwest of the star Ο1 Cygni.[5] It lies at a distance of approximately 12.5 kly from the Sun.[2] The nebula was discovered on May 8, 1883, by American astronomer Edward C. Pickering.[6]
| Emission nebula | |
|---|---|
| Planetary nebula | |
Hubble Space Telescope (HST) image of NGC 6884 | |
| Observation data: J2000 epoch | |
| Right ascension | 20h 10m 23.64012s[1] |
| Declination | +46° 27′ 39.5478″[1] |
| Distance | 12.5 kly (3.830 kpc)[2] ly |
| Apparent dimensions (V) | 0.127′[2] |
| Constellation | Cygnus |
| Physical characteristics | |
| Radius | 0.23 ly |
| Designations | PNG 082.1+07.0[3], NGC 6766[4] |
This nebula consists of the cast-off outer atmosphere of an aging star. It is young and compact with a kinematic age of 720 years.[7] The nebula is point-symmetric with arcs forming an S-shaped inner core;[8] the shape is likely explained by bipolar outflows with a velocity of 55 km/s.[7] The core is surrounded by a filamentary ring structure that is inclined at an angle of around 40–45° to the line of sight from the Earth. The core has an overall shape of a prolate ellipsoid with axis ratios of 1.6:1 and is inclined by 40°.[8] The expansion velocity of the nebula ranges over 19–25 km/s. The central star has a temperature of ~100,000 K[7] and a class of WN b?.[3]
