| Emission nebula | |
|---|---|
| Planetary nebula | |
 Hubble Space Telescope (HST) image of NGC 6884 | |
| Observation data:J2000epoch | |
| 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] |
| See also:Lists of nebulae | |
NGC 6884 is aplanetary nebula[4] located in theconstellationCygnus, less than a degree to the southwest of the starΟ1 Cygni.[5] It lies at a distance of approximately 12.5 kly from theSun.[2] The nebula was discovered on May 8, 1883, by American astronomerEdward C. Pickering.[6]
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 of55 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 prolateellipsoid 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 aclass ofWN b?.[3]
Media related toNGC 6884 at Wikimedia Commons