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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.
As petrologic type increases from type 3.1 through 3.9, profound mineralogical changes occur, starting in the dusty matrix, and then increasingly affecting the coarser-grained components like chondrules. Type 3.9 chondrites still look superficially unchanged because chondrules retain their original appearances, but all of the minerals have been ...
While CM chondrules are smaller than average in diameter (~300 micrometer), CO chondrules are exceptionally small (~170 um). [ 31 ] [ 32 ] This may be a survivor bias : consider that the water which dissolves CM chondrules successfully eliminates those which are already small, while those which were large may remain to be observed, though with ...
List of NGC objects (1–1000) List of NGC objects (1001–2000) List of NGC objects (2001–3000) List of NGC objects (3001–4000) List of NGC objects (4001–5000) List of NGC objects (5001–6000) List of NGC objects (6001–7000) List of NGC objects (7001–7840) List of IC objects; List of Messier objects; List of Caldwell objects
7.6 C55 NGC 7009: Saturn Nebula: Planetary Nebula: 1.4 Aquarius: 8 C56 NGC 246: Skull Nebula [10] Planetary Nebula: 1.6 Cetus: 8 C57 NGC 6822: Barnard's Galaxy: Barred irregular galaxy: 2,300 Sagittarius: 9 C58 NGC 2360: Caroline's Cluster: Open Cluster: 3.7 Canis Major: 7.2 C59 NGC 3242: Ghost of Jupiter: Planetary Nebula: 1.4 Hydra: 9 C60 NGC ...
The nebulae listed by Barnard have become known as Barnard objects. [2] A 1919 version of the catalogue listed 182 nebulae; [3] by the time of the posthumously published 1927 version, it listed 369. [4] Barnard's niece and assistant Mary Ross Calvert, also an astronomer and astrographer, took an important part in creating the catalogue. [5]
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.
[3] In 2006 a classification was published that assigned 7 groups to the primitive achondrites, but the classification remains controversial. The authors define primitive achondrites as meteorites "that exceeded their solidus temperature on the parent body" and thus would partially melt. Meteorites that have been fully melted are included if ...