Disk Lifetimes as a Function of Stellar Mass and Environments in Young Stellar Clusters

Lada博士和她的团队研究了拱星盘寿命对恒星质量和星团环境的依赖性。这对于理解盘发展成行星系统是很重要的。研究人员将联合收割机近红外FLAMINGOS光谱学和光度学结合起来，利用档案中红外斯皮策光度学研究了分子云英仙座、猎户座A、猎户座B和摩羯座OB 1中8个年轻（约1-2百万年）嵌入星团样本的恒星种群。星团的样本涵盖了一系列的大小，恒星种群，恒星密度和形态。光谱数据提供了灭绝，恒星光谱类型，年龄中位数，年龄分布，恒星质量和每个星团内恒星的分布。导出的消光结合斯皮策中红外测光获得的源，这是一个指标，用于区分源与磁盘和信封，源与光学厚磁盘，源与光学薄贫血磁盘，和无盘源的固有红外过剩。盘的寿命可能取决于恒星质量和集群环境，这里的目标是评估的恒星与恒星质量的依赖关系的分数，并评估磁盘分数集群环境，如集群恒星密度，恒星人口，形态和年龄中位数的依赖。这项研究还为研究生和青年科学家提供天文学研究方面的培训，并让他们参加教育推广活动。

Dr. Lada and her team study the dependence of circumstellar disks lifetimes on stellar mass and stellar cluster environment. This is important to understand the disk development into planetary systems. The researchers combine near-infrared FLAMINGOS spectroscopy and photometry to study the stellar populations for a sample of eight young (about 1-2 million years old) embedded clusters in the molecular clouds Perseus, Orion A, Orion B and Mon OB1 with archival mid-IR Spitzer photometry. The sample of clusters covers a range of sizes, stellar populations, stellar densities and morphologies. The spectroscopic data provide extinction, stellar spectral types, median ages, age spreads, stellar masses and distribution of stars within each cluster. The derived extinction is combined with Spitzer mid-infrared photometry to obtain the intrinsic infrared excess for the sources, which is an indicator for distinguishing sources with disks and envelopes, sources with optically thick disks, sources with optically thin anemic disks, and diskless sources. The disks lifetimes might depend on both stellar mass and cluster environment and the goals here are to assess the dependence of fraction of stars with discs on stellar mass, and to evaluate the dependence of disks fraction on cluster environments such as cluster stellar density, stellar population, morphology, and median ages. This research also provides training for graduate students and young scientists in astronomical research, and they participate in educational outreach activities.