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The Chamaeleon complex is a large star forming region (SFR) that includes the Chamaeleon I, Chamaeleon II, and Chamaeleon III dark clouds. It occupies nearly all of the constellation Chamaeleon and overlaps into Apus, Musca, and Carina. The mean density of X-ray sources is about one source per square degree. ==Chamaeleon I dark cloud== The Chamaeleon I (Cha I) cloud is one of the nearest active star formation regions at ~160 pc.〔 It is relatively isolated from other star-forming clouds, so it is unlikely that older pre-main sequence (PMS) stars have drifted into the field. The total stellar population is 200-300.〔 The Cha I cloud is further divided into the North cloud or region and South cloud or main cloud. HD 97300 emits X-rays, illuminates the reflection nebula Ced 112 and is one of the highest mass members of the Cha I cloud, spectral type B9V, a Herbig Ae/Be star without emission lines.〔 Cha Halpha 1 is an M8 object in the Chamaeleon I dark cloud that was determined in 1998 to be an X-ray source and as such is the first X-ray emitting brown dwarf found. There are some seventy to ninety X-ray sources in the Chamaeleon I star forming region. The Uhuru X-ray source (4U 1119-77) is within the Chamaeleon I cloud. This source region within the Chamaeleon I dark cloud was observed by ROSAT on February 9 at 22:14:47 UTC to February 18, 1991, 17:59:12 UTC, and on March 6, 1991, from 09:12:19 to 13:05:13 UTC.〔 This cloud contains both "weak" T Tauri (WTT) stars and "classical" T Tauri (CTT) stars.〔 Chamaeleon I X-ray ROSAT source 66 is at RA 11h 17m 36.4-37.9s Dec -77° 04' 27-50", is a CTT, Chamaeleon I No. T56, aka CTT star HM 32.〔 The Chamaeleon I dark cloud was observed with the Imaging Proportional Counter (IPC) on board the Einstein Observatory for 2.5 h on January 23–24, 1981, identifying some 22 X-ray sources. None of these sources was closer than 8' to 4U 1119-77. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Chamaeleon complex」の詳細全文を読む スポンサード リンク
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