大尺度赫比格-哈罗天体的光学研究进展  

Progress in Optical Studies on Parsec-scale Herbig-Haro Flows

作　　者：王敏[1] 

机构地区：[1]中国科学院紫金山天文台,南京210008

出　　处：《天文学进展》2002年第1期59-73,共15页Progress In Astronomy

基　　金：国家 973项目(G19990754)资助课题

摘　　要：近期大视场ＣＣＤ成像观测表明。由年轻星激发的部分赫比格－哈罗（ＨＨ）天体的尺度范围 超过 １ｐｃ，比过去认识的 ＨＨ天体的尺度大了一个量级。目前的观测己经发现 ｐｃ尺度的 ＨＨ天 体有数十个，表明ＨＨ天体达到ｐｃ尺度是很普遍的，这将深刻地改变人们对年轻星与其周围环境 作用的认识．综合评述了ｐｃ尺度ＨＨ天体的观测性质，讨论了巨ＨＨ天体对恒星形成的重大意 义及其对周围星际介质的物理和化学影响．Recent observations demonstrate that outfiows traced by Herbig-Haro (HH) objects can extend for parsecs from their driving sources, at 1east an order of magnitude larger than previous work. Some well-known HH objects such as HH 34 and HH 111 are verified to be parsec-scale HH flows. Up to now, dozens of giant HH flows have been reported in the Orion, Taurus, Cepheus and Perseus molecular cloud complexes. It thus appears that it is common for HH flows to attain parsec-scale dimensions. The ubiquity of parsec-scale HH flows profoundly ajters our view of the impact of young stars on their environment. They provide a fossil record of the outflow behavior and mass loss rate from a young star over a significant fraction of the 10～5 year outflow phase, and provide indirect clues to the aecretion history of the forming star. Many parsec--scale HH outflows with multiple internal working surfaces and S--shaped point symmetry about the central sources show evidence for variability of ejection velocity and orientation of the source jets. Giaot HH flows with longer or comparable lengthes to associated CO outflows, imply that HH flows power CO flows. Giant HH flows are capable of heating, ionizing, and dissociating cloud material over parsec scale distances and may play a role in the chemical rejuvenation of clouds and the generation of the turbulent motions observed in molecular clouds as well as the self regulation of star formation.

关 键 词：恒星 赫比格-哈罗天体 星际介质 喷流 外流 HH天体 CCD成像观测 

分 类 号：P155[天文地球—天文学]