MBM 12：高银河纬度的年轻原行星盘
MBM 12: young protoplanetary discs at high galactic latitude
摘要：
我们介绍了斯皮策红外观测来限制MBM 12中年轻金牛座T星的盘和尘埃演化，MBM 12是一个高纬度的恒星形成云，年龄为200万年，距离为275 pc。该区域包含12个金牛座T星系统，主要光谱类型在K3和M6之间，其中5个是弱线，其余是经典金牛座T星。我们首先使用MIPS和文献测光编译的光谱能量分布MBM 12中的12个成员，并推导出他们的IR过剩。IRS光谱分析与新开发的两层温度分布（TLTD）光谱分解方法。对于7 T金牛星检测到红外过剩，我们分析其固态特征，得出尘埃的质量平均粒度，成分和结晶度等属性。我们发现在镁橄榄石顽火辉石范围内的空间梯度，与更多的顽火辉石存在于温暖的地区。事实上，我们看到的尘埃性质的径向依赖表明，径向混合是不是很有效的光盘这些年轻的金牛座T星。SED分析表明，MBM 12的盘，在一般情况下，经历快速的内部盘清除，而二进制源有更快的discevolution。尘埃颗粒的演化似乎与恒星的性质无关，但与星盘的性质（如耀斑和吸积速率）有一定的关系。
英文摘要：
(abridged) We present Spitzer infrared observations to constrain disc and dust evolution in young T Tauri stars in MBM 12, a star-forming cloud at high latitude with an age of 2 Myr and a distance of 275 pc. The region contains 12 T Tauri systems, with primary spectral types between K3 and M6; 5 are weak-line and the rest classical T Tauri stars. We first use MIPS and literature photometry to compile spectral energy distributions for each of the 12 members in MBM 12, and derive their IR excesses. The IRS spectra are analysed with the newly developed two-layer temperature distribution (TLTD) spectral decomposition method. For the 7 T Tauri stars with a detected IR excess, we analyse their solid-state features to derive dust properties such as mass-averaged grain size, composition and crystallinity. We find a spatial gradient in the forsterite to enstatite range, with more enstatite present in the warmer regions. The fact that we see a radial dependence of the dust properties indicates that radial mixing is not very efficient in the discs of these young T Tauri stars. The SED analysis shows that the discs in MBM 12, in general, undergo rapid inner disc clearing, while the binary sources have faster discevolution. The dust grains seem to evolve independently from the stellar properties, but are mildly related to disc properties such as flaring and accretion rates.
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。
