This is my personal tribute to one of my most admired astronomers: Edward Emerson Barnard
http://en.wikipedia.org/wiki/Edward_Emerson_BarnardYoung stars in bright-rimmed or comet-shaped clouds are likely to have been formed by triggering, which would result in an age spread of several Myrs between the member stars or star groups formed in the sequence. In the Orion star-forming region for example, there is concrete evidence of triggered star formation as manifested by the bright-rimmed clouds (BRCs) in the vicinity of O stars (Lee et al. 2005, I). These BRCs are considered the remnant of molecular clouds that have been photoionized by a nearby massive star (Sugitani et al. 1991, 1994). B35 is a BRC associated with an H II region excited by the O8 III star Lambda Ori and surrounded by a ring-shaped molecular cloud (Lang et al. 2000). (1982) find some 80 Ha stars in the Lambda Ori region. structure extending from either side of Lambda Ori to B35. It is likely that Lambda Ori is the triggering source responsible for the star formation in B35. It is found that photoevaporative flows (Hester et al. 1996) stream out of the surfaces of them; this is a demonstration of the interaction between a massive star and a molecular cloud.
Credits: Hsu-Tai Lee W. P. Chen Institute of Astronomy, National Central University, 300 Jungda Road, Jungli 32054, Taiwan
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