This fascinating
molecular cloud, designated LBN 762, is located in the constellation of Aries at a declination of +18 degrees. The cloud shapes here are fantastic and I like that parts of the cloud are highlighted with a dusty brown color. I especially like the jagged semi-circular cloud at bottom center.
This formation is sometimes referred to as the Drunken Dragon Nebula, which is another example of why I detest the use of nicknames except in a few special cases.
I have always been intrigued by molecular clouds and I am eager to better understand them. I found this interesting quote on a web site by Sergio Kaminsky, who quoted it from the Handbook of Star Forming Regions Vol. II, Astronomical Society of the Pacific, 2008 Bo Reipurth, editor:
“High-latitude clouds are predominately diffuse or translucent and are thus difficult to detect on photographic surveys. The notable exceptions are the Lynds Dark Nebulae identified by Lynds (1962) using Palomar Sky Survey plates covering the sky north of δ = −33◦ , and extended regions of faint nebulosity seen in deep imaging surveys. The latter were first identified on the Palomar Sky Survey plates by Lynds (1965a) and in an unpublished study (circa 1968) by C. R. Lynds. Sandage (1976) subsequently showed that interpretation of these structures as reflection nebulosities illuminated by the Galactic plane yielded surface brightness predictions deduced from the neutral hydrogen column density that were consistent with observations.
Molecular clouds are classed, following van Dishoeck & Black (1988), into three categories based primarily on the visual extinction (AV ) along the line of sight through the cloud. Diffuse clouds are identified by AV < 1 magnitude, dark clouds are marked by AV > 5 magnitudes, and translucent clouds are those with intermediate values of AV . This set of criteria also reflects the changes in astrochemistry (van Dishoeck & Black 1988). While the chemistry in diffuse clouds is largely due to photoprocesses and that in dark clouds is dominated by collisional processes, in the translucent clouds we find the conditions in which carbon is being bound up in the form of CO.”
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