对近距离米拉变量的 CO(3-2) 调查
摘要
对位于太阳500 pc范围内的可见光下氧富米拉变星星系进行了CO(3-2)发射的调查。检测到36个66个被检查的星体周围有分子包围层。其中一些星体的外流速度小于以往在CO中检测到的任何米拉星。 ejected material的平均终端速度为7.0 km/sec，这是之前通过红外标准挑选的米拉星中找到的约一半的数值。在光谱类型早于M 5.5的星体中未检测到任何星体。终端速度随着星体光谱温度的降低而增加，这符合辐射驱动风的预期。对检测到的对象计算了质量损失率，发现红外颜色与质量损失率之间不存在相关性。质量损失率与远红外光度相关，但有些星体似乎拥有广泛的尘埃包围层而无可检测的分子风。发现一种幂律关系适用于质量损失率与 ejected material的终端速度之间。这一关系表明，当外流速度大于17 km/sec时，尘埃包围层应在近红外和可见光谱区域呈现高度透明度。在观察到的外流速度范围的低端，尘埃漂移速度可能高 enough to lead to the destruction of the grains via sputtering. Half of the stars which were detected were re-observed in the CO(4-3) transition. A comparison of the outflow velocities obtained from these observations with those obtained by other investigators at lower frequencies shows no evidence for gradual acceleration of the outer molecular envelope.
引用
@article{arxiv.astro-ph/9501020,
title = {A CO(3-2) Survey of Nearby Mira Variables},
author = {K. Young},
journal= {arXiv preprint arXiv:astro-ph/9501020},
year = {2009}
}
备注
27 pages postscript with embedded figures, email: [email protected]