Observational studies of pre-main-sequence evolution.
Observational studies of pre-main-sequence evolution.
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DOI：
10.1086/190641
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发表时间：
1979-12
影响因子：
8.7
通讯作者：
M. Cohen;L. Kuhi
中科院分区：
文献类型：
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作者：
M. Cohen;L. Kuhi
获得了分辨率为7埃的4270 - 6710埃的光学扫描仪数据，约600小时。阿尔法帽。在赫比格和拉奥的金牛座T星汇编中列出的发射星，以及在原始的H。阿尔法帽。调查。这些被用来获得光谱类型，红化校正，和发射线强度，并结合红外宽带测量到3.5。Mu.. m，以提供辐射热光度和有效温度。给出了金牛座-御夫座复合体、猎户座、NGC 2264、NGC 7000/IC 5070和蛇夫座星协的H-R图。得出以下结论：大多数H。阿尔法帽。在H-R图中，发射星位于对流轨道上，它们的分布与任何已发表的动力学演化轨道都不对应。最H..阿尔法帽。发射星的光谱类型为晚K型，光度等级在III和V之间。由H-R图得出的半径和质量分别在1和5 R/亚太阳/之间和0.2和3 M/亚太阳/之间。d（log N）/d（log M）的值范围为-1.35至-2.9，对于三个最佳观测组，与Salpeter初始质量函数的-1.35一致。星星的形成在小于10/sup 4/到大约6 × 10/sup 6/年的时间尺度上是不相同的。星星形成的总效率约为10%。大部分的灭绝发生在黑暗的云层中，而不是在星周的信封。因此，高质量的恒星可能会优先在云的致密核心形成，而低质量的恒星可能会在整个云中形成。很可能所有的金牛座T星都是双星。«少
Optical scanner data from 4270 to 6710 A with a resolution of 7 A have been obtained for some 600 H..cap alpha.. emission stars listed in the compilation of T Tauri stars by Herbig and Rao and in the original H..cap alpha.. surveys. These are used to obtain spectral types, reddening corrections, and emission-line strengths and are combined with infrared broad-band measurements out to 3.5 ..mu..m to provide bolometric luminosities and effective temperatures. H-R diagrams are presented for the Taurus-Auriga complex, Orion, NGC 2264, NGC 7000/IC 5070, and the rho Ophiuchi association. The following conclusions are reached: Most H..cap alpha.. emission stars lie on convective tracks in the H-R diagram, and their distribution does not correspond to any published dynamical evolutionary tracks. Most H..cap alpha.. emission stars are of spectra type late K and luminosity class between III and V. Radii and masses derived from the H-R diagram lie between 1 and 5 R/sub sun/ and between 0.2 and 3 M/sub sun/, respectively. The value of d (log N)/d (log M) ranges from -1.35 to -2.9 and for the three best-observed groups is consistent with the -1.35 of the Salpeter initial mass function. Star formation is not coeval on amore » time scale of less than a10/sup 4/to approx.6 x 10/sup 6/ years. The overall efficiency of star formation is approx.10%.6.. The bulk of the extinction occurs within the dark clouds rather than in circumstellar envelopes. High-mass stars may therefore form preferentially in the dense cores of clouds, and low-mass stars may form throughout the cloud. It is very likely that all close pairs of T Tauri stars are binaries.« less