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Chondrules in the chondrite classification Grassland. A millimeter scale is shown. Chondrules in the Carbonaceous Chondrite NWA 13887. A chondrule (from Ancient Greek χόνδρος chondros, grain) is a round grain found in a chondrite. Chondrules form as molten or partially molten droplets in space before being accreted to their parent asteroids.
Planetary Nebula: 2.2 Cygnus: 10 C16 NGC 7243 Open Cluster: 2.5 Lacerta: 6.4 C17 NGC 147 Dwarf Spheroidal Galaxy: 2,300 Cassiopeia: 9.3 C18 NGC 185 Dwarf Spheroidal Galaxy: 2,300 Cassiopeia: 9.2 C19 IC 5146: Cocoon Nebula: Open Cluster and Nebula: 3.3 Cygnus: 7.2 C20 NGC 7000: North America Nebula: Nebula: 2.6 Cygnus: 4 C21 NGC 4449 Irregular ...
The RCW Catalogue (from Rodgers, Campbell & Whiteoak) is an astronomical catalogue of Hα-emission regions in the southern Milky Way, described in (Rodgers et al. 1960).It contains 182 objects, including many of the earlier Gum catalogue (84 items) objects.
From this work Sharpless published his catalog of H II regions in two editions: the first in 1953, with 142 nebula; [3] and the second and final edition in 1959, with 312 nebulae. [2] [4] Sharpless coordinates are based on the star catalogs Bonner Durchmusterung (BD) and Cordoba Durchmusterung (CD), but the second release was adjusted to the ...
In astronomy, Bok globules are isolated and relatively small dark nebulae containing dense cosmic dust and gas from which star formation may take place. Bok globules are found within H II regions, and typically have a mass of about two [1] to 50 solar masses contained within a region about a light year or so across (about 4.5 × 10 47 m 3). [2]
[1] [2] They are believed to be a common feature of the evolution of planetary nebulae, but can only be resolved in the nearest examples. [2] They are generally larger than the size of the Solar System (i.e. the orbit of Pluto ), with masses of around 0.00001 times the mass of the Sun , which is comparable to the mass of the Earth .
The Catalogue of Nebulae and Clusters of Stars was first published in 1786 by William Herschel in the Philosophical Transactions of the Royal Society of London. [1] In 1789, he added another 1,000 entries, [2] and finally another 500 in 1802, [3] bringing the total to 2,500 entries. This catalogue originated the usage of letters and catalogue ...
IC 5146 (also Caldwell 19, Sh 2-125, Barnard 168, and the Cocoon Nebula) is a reflection [2] /emission [3] nebula and Caldwell object in the constellation Cygnus. The NGC description refers to IC 5146 as a cluster of 9.5 mag stars involved in a bright and dark nebula.