Planetary nebula, any of a class of bright nebulae that are expanding shells of luminous gas expelled by dying stars. They have a relatively round compact appearance rather than the chaotic patchy shapes of other nebulae—hence their name, which was give
Explore planetary nebulae. Learn the definition of a planetary nebula and understand its structure and chemical composition. Find out how a...
Forms and Structure of the Planetary Nebula Compared with other types of nebulae, planetary nebulae are quite small. Typically, they have a radius of approximately 1 light year. However, there is a large variation in the size. The Cat's Eye Nebula has a radius of approximately 0.2 light ...
Define planetary gear. planetary gear synonyms, planetary gear pronunciation, planetary gear translation, English dictionary definition of planetary gear. Noun 1. planetary gear - an outer gear that revolves about a central sun gear of an epicyclic train
Planetary nebula IC418 (Hubble Space Telescope image), showing the central white dwarf star. The false color image uses the 6584Å [NII] forbidden line (red channel), Hα (green channel), and the 5007Å [OIII] forbidden line (blue channel), similar to Fig. 17.1.Source: NASA and ...
Define Planetary Sciences. Planetary Sciences synonyms, Planetary Sciences pronunciation, Planetary Sciences translation, English dictionary definition of Planetary Sciences. n. The branch of astronomy that deals with the phenomena and objects found in t
If the IAU’s definition were consistently applied, the crust of Europa would be a “non-planetary crust” because crusts would not be characteristic of planets and in particular Europa’s would be an example of a crust from a non-planet. The same would be true for planetary albedo, ...
Re: APOD: Planetary Nebula Project (2011 Feb 18) Post by Chris Peterson » Fri Feb 18, 2011 5:44 am garry wrote:In the picture shown, there are two distinct types; One type spherical, the other type seems to be "pinched " in the middle of a tubular section. Now if a star col...
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In this paper we review the evolutionary paths that lead to the different types of planetary nebulae nuclei, including hydrogen and helium-burning central stars. Starting from the empirical definition of WR central stars, based on stellar spectra, we examine the theoretical work produced to account...