NGC 6884

NGC 6884
Emission nebula
Planetary nebula
Hubble Space Telescope (HST) image of NGC 6884
Observation data: J2000 epoch
Right ascension20h 10m 23.64012s[1]
Declination+46° 27′ 39.5478″[1]
Distance12.5 kly (3.830 kpc)[2] ly
Apparent dimensions (V)0.127′[2]
ConstellationCygnus
Physical characteristics
Radius0.23 ly
DesignationsPNG 082.1+07.0[3], NGC 6766[4]
See also: Lists of nebulae

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]

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]

  1. ^ a b Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference Stanghellini2008 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Weidmann2011 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference simbad was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Sinnott1997 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference cseligman was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference Miranda1999 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Palen2002 was invoked but never defined (see the help page).