Search results
Results from the WOW.Com Content Network
Slipher and Edwin Hubble continued to collect the spectra from many different nebulae, finding 29 that showed emission spectra and 33 that had the continuous spectra of star light. [18] In 1922, Hubble announced that nearly all nebulae are associated with stars and that their illumination comes from star light.
Planetary nebulae, represented here by the Ring Nebula, are examples of emission nebulae. An emission nebula is a nebula formed of ionized gases that emit light of various wavelengths. The most common source of ionization is high-energy ultraviolet photons emitted from a nearby hot star .
Reflection nebula are usually blue because the scattering is more efficient for blue light than red (this is the same scattering process that gives us blue skies and red sunsets). Reflection nebulae and emission nebulae are often seen together and are sometimes both referred to as diffuse nebulae. Some 500 reflection nebulae are known.
The nebula measures around two light years long from end to end, and contains a central white dwarf with an apparent magnitude of 11. The inner layers of the nebula were formed some 1,500 years ago. [4] The two ends of the nebula are marked by FLIERs, lobes of fast moving gas often tinted red in false-color pictures. [5]
Based on the expansion rate, the estimated age of the nebula is 3,080 years. [5] The central star of the planetary nebula is a subdwarf O star with a spectral type of sdO. [7] The best fit model for this star gives an effective temperature of 100 kK, with 5,250 times the luminosity of the Sun [5] and 60.5% of the Sun's mass. [6]
Jewel Bug Nebula, [citation needed] Gummy Bear Nebula [5] See also: Lists of nebulae NGC 7027, also known as the Jewel Bug Nebula or the Magic Carpet Nebula , [ 6 ] is a very young and dense planetary nebula [ 7 ] located around 3,000 light-years (920 parsecs ) from Earth in the constellation Cygnus .
IC 418, also known as the Spirograph Nebula, is a planetary nebula located in the constellation of Lepus about 3,600 ly away from Earth. It spans 0.3 light-years across. The central star of the planetary nebula, HD 35914 , is an O-type star with a spectral type of O7fp. [ 4 ]
The M42 nebula is estimated to be 25 light-years across (so its apparent size from Earth is approximately 1 degree). It has a mass of about 2,000 times that of the Sun. Older texts frequently refer to the Orion Nebula as the Great Nebula in Orion or the Great Orion Nebula. [7]