The Egg Nebula ( RAFGL 2688 , CRL 2688 , The Egg Nebula ) is a bipolar protoplanetary nebula located at a distance of about 3,000 light-years from the Sun. For the first time, the properties of the nebula were described in 1975 on the basis of data from a survey at a wavelength of 11 μm conducted by AFGL ( English Air Force Geophysical Laboratory ) from 1971 to 1974. Prior to this, Fritz Zwicky cataloged this object as a pair of galaxies .
| Nebula Egg | |
|---|---|
| protoplanetary nebula | |
 RAFGL 2688, Egg Nebula | |
| Research history | |
| Designations | RAFGL 2688, [1] Egg, [1] |
| Observational data ( Age J2000.0 ) | |
| Right ascension | |
| Declination | |
| Distance | 3000 St. years [2] |
| Visible magnitude (V) | 14.0 [1] |
| Visible Dimensions (V) | 30 ″ × 15 ″ |
| Constellation | Swan |
| physical characteristics | |
| Spectral class | |
| Radius | 0.2 St. years |
Observed structure
The most remarkable feature of the nebula is the rows of bright arches and circles around the central star. The light of the star is hidden from the observer by a dense layer of gas and dust. However, light penetrates through thinner sections of the dust envelope, illuminating the outer layers of the gas and creating the arches we observe.
The dust envelope around the central star is probably disc-shaped. The polar currents visible in the image show that the object has an angular momentum created, apparently, by an accretion disk . The geometry of the disk should explain the variable thickness of the shell, allowing light to pass along the axis of the disk and highlight the outer layers of gas, but blocking the light from us along the edge of the disk. Although dust discs were observed around several stars that left the asymptotic branch of giants (S. De Ruyter et al., 2006), the presence of a disc in this nebula has not been confirmed.
The image of the Egg nebula was obtained by the WFPC2 camera ( English Wide Field and Planetary Camera 2 ) of the Hubble telescope .
The nebula emits polarized light , [4] which can be observed with a medium-sized telescope. [5]
Notes
- ↑ 1 2 3 4 5 6 SIMBAD Astronomical Database . Results for Egg Nebula . Date of treatment January 5, 2007.
- ↑ 1 2 Hubble Images Searchlight Beams from a Preplanetary Nebula . Date of appeal May 24, 2017.
- ↑ Merrill KM, Stein WA 2-14 mum stellar spectrophotometry. III. AFCRL sky survey objects // Publications of the Astronomical Society of the Pacific - University of Chicago Press , 1976. - Vol. 88. - P. 874–887. - ISSN 0004-6280 ; 1538-3873 - doi: 10.1086 / 130039
- ↑ Raghvendra Sahai et al. The Structure of the Prototype Bipolar Protoplanetary Nebula CRL 2688 (Egg Nebula): Broadband, Polarimetric, and H2 Line Imaging with NICMOS on the Hubble Space Telescope (Eng.) // The Astrophysical Journal : journal. - IOP Publishing 1998 .-- January ( vol. 492 , no. 2 ). - P. L163 — L167 . - DOI : 10.1086 / 311108 . - .
- ↑ Proto-planetary Nebulae . Date of appeal May 24, 2017.
- Hubble Finds Searchlight Beams and Multiple Arcs around a Dying Star . STScI Press release: Space Telescope Science Institute . January 16, 1996.
- De Ruyter et al. Keplerian discs around post-AGB objects: a common phenomenon? Astronomy & Astrophysics 448, 641–653 (2006).
Links
- Merrifield, Michael Egg Nebula . Deep Space Videos . Brady Haran.