VMR-D中的前主序列变量：通过斯皮策-IRAC变率识别金牛座T型吸积原恒星
Pre-Main Sequence variables in the VMR-D : identification of T Tauri-like accreting protostars through Spitzer-IRAC variability
摘要：
我们提出了一个年轻的恒星物体的红外线变化的研究，通过两个斯皮策-IRAC的船帆座分子云D（VMR-D）的观测时间间隔约6个月的图像。通过使用相同的空间红外仪器，这项研究消除了所有不必要的影响，通常不可避免的比较时，从不同的仪器获得的目录。VMR-D地图覆盖约1.5平方度。恒星形成活跃的地方我们感兴趣的吸积前主序星的光度变化是由于间歇性事件的磁盘吸积（即活跃的金牛T星和EXor型对象）。这些可变物体是从超过170，000个以S/N比> 5探测到的源的目录中选出的。我们搜索样本的变量，其光度特性接近那些已知的EXOR的。这些后者被监测在一个更系统的方式比金牛T星和机制，规范观察到的现象是完全相同的。因此，EXor行为的模态通常被用作选择变量的驱动标准。我们选择了19个真正的候选人，构成了一个定义明确的新的可变目标样本，以供进一步调查。其中，10个源呈现斯皮策MIPS 24微米对应物，并被分类为3个I类，5个平坦光谱和2个II类物体，而其他9个源的光谱能量分布与I类以上的相位兼容。这与已知EXor的小样本是一致的，并表明吸积耀斑或EXor阶段可能是I/II类跃迁。我们还提出了新的处方，可以在未来的搜索在大型IR数据库中的吸积变量是有用的。
英文摘要：
We present a study of the infrared variability of young stellar objects by means of two Spitzer-IRAC images of the Vela Molecular Cloud D (VMR-D) obtained in observations separated in time by about six months. By using the same space-born IR instrumentation, this study eliminates all the unwanted effects usually unavoidable when comparing catalogs obtained from different instruments. The VMR-D map covers about 1.5 square deg. of a site where star formation is actively ongoing. We are interested in accreting pre-main sequence variables whose luminosity variations are due to intermittent events of disk accretion (i.e. active T Tauri stars and EXor type objects). The variable objects have been selected from a catalog of more than 170,000 sources detected at a S/N ratio > 5. We searched the sample of variables for ones whose photometric properties are close to those of known EXor's. These latter are monitored in a more systematic way than T Tauri stars and the mechanisms that regulate the observed phenomenology are exactly the same. Hence the modalities of the EXor behavior is adopted as driving criterium for selecting variables in general. We selected 19 bona fide candidates that constitute a well-defined sample of new variable targets for further investigation. Out of these, 10 sources present a Spitzer MIPS 24 micron counterpart, and have been classified as 3 Class I, 5 flat spectrum and 2 Class II objects, while the other 9 sources have spectral energy distribution compatible with phases older than Class I. This is consistent with what is known about the small sample of known EXor's, and suggests that the accretion flaring or EXor stage might come as a Class I/II transition. We present also new prescriptions that can be useful in future searches for accretion variables in large IR databases.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
