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] |
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]
References
[edit]- ^ a b Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c Stanghellini, Letizia; et al. (December 10, 2008). "The Magellanic Cloud Calibration of the Galactic Planetary Nebula Distance Scale". The Astrophysical Journal. 689 (1): 194–202. arXiv:0807.1129. Bibcode:2008ApJ...689..194S. doi:10.1086/592395. S2CID 119257242.
- ^ a b Weidmann, W. A.; Gamen, R. (February 2011). "Central stars of planetary nebulae: New spectral classifications and catalogue". Astronomy and Astrophysics. 526: 16. arXiv:1010.5376. Bibcode:2011A&A...526A...6W. doi:10.1051/0004-6361/200913984. S2CID 118704591. A6.
- ^ a b "NGC 6884". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-10-06.
- ^ Sinnott, Roger W.; Perryman, Michael A. C. (1997). Millennium Star Atlas. Vol. 3. Sky Publishing Corporation and the European Space Agency. p. 1108. ISBN 0-933346-84-0.
- ^ Seligman, Courtney. "NGC Objects: NGC 6850 - 6899". Retrieved 2020-10-03.
- ^ a b c Miranda, Luis F.; et al. (March 1999). "Multiwavelength Imaging and Long-Slit Spectroscopy of the Planetary Nebula NGC 6884: The Discovery of a Fast Precessing, Bipolar Collimated Outflow". The Astronomical Journal. 117 (3): 1421–1432. Bibcode:1999AJ....117.1421M. doi:10.1086/300774.
- ^ a b Palen, Stacy; et al. (May 2002). "Hubble Space Telescope Expansion Parallaxes of the Planetary Nebulae NGC 6578, NGC 6884, NGC 6891, and IC 2448". The Astronomical Journal. 123 (5): 2666–2675. arXiv:astro-ph/0202003. Bibcode:2002AJ....123.2666P. doi:10.1086/339838. S2CID 119426665.
External links
[edit]Media related to NGC 6884 at Wikimedia Commons
Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
View the detailed Guide of Psilotum nudum: Detailed Study Of Psilotum Nudum (Whisk Fern), Classification, Anatomy, Reproduction