Protoplanetary disk masses in NGC 2024: Evidence for two populations
Protoplanetary disk masses in NGC 2024: Evidence for two populations
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DOI：
10.1051/0004-6361/201937403
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发表时间：
2020-04
影响因子：
6.5
通讯作者：
S. V. Terwisga;E. Dishoeck;R. Mann;J. Francesco;N. Marel;M. Meyer;S. Andrews;J. Carpenter;J. Eisner;C. Manara;Jonathan P. Williams
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文献类型：
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作者：
S. V. Terwisga;E. Dishoeck;R. Mann;J. Francesco;N. Marel;M. Meyer;S. Andrews;J. Carpenter;J. Eisner;C. Manara;Jonathan P. Williams
上下文在致密、大质量恒星形成区域的原行星盘受到其环境的强烈影响。这种环境影响如何随着时间的推移而变化是对盘演化和外部光蒸发模型的重要约束。目标。我们描述了年轻（0.5百万年）NGC 2024星团核心179个盘的尘埃排放。通过研究磁盘质量如何在集群内变化，并将这些磁盘与其他区域的磁盘进行比较，我们的目标是确定外部光蒸发如何随着时间的推移影响磁盘特性。方法.使用阿塔卡玛大型毫米/亚毫米阵列，在225 GHz观测到以NGC 2024 FIR 3为中心的2.9“× 2.9”镶嵌，分辨率为0.25“，或约100 Au。成像区域包含179个在红外波长下识别的盘，7个新的盘候选者和几个原恒星。结果椎间盘的总体检出率为32 ± 4%。除了一个巨大的（R = 300 Au）过渡盘外，很少有盘被分辨出来。偶然地，我们观察到一个毫米耀斑的X射线明亮的年轻恒星对象（YSO），并解决连续辐射从0类YSO在FIR 3核心。两个不同的星盘群存在：一个更大的星盘群在东部，沿着密集的分子脊，那里有FIR 1-5 YSO，探测率为45 ± 7%。在西方人群中，对于IRS 1，仅检测到15 ± 4%的圆盘。结论. NGC 2024拥有两个不同的磁盘种群。沿着沿着密集的分子脊是年轻的（0.2-0.5百万年），并部分屏蔽了IRS 2b的远紫外辐射;它们的质量与孤立的1-3百万年前的SFR相似。西部的种群年龄较大，海拔较低，可能受到IRS 1和IRS 2b的外部光蒸发的影响。然而，这些圆盘可能开始质量较低。
Context. Protoplanetary disks in dense, massive star-forming regions are strongly affected by their environment. How this environmental impact changes over time is an important constraint on disk evolution and external photoevaporation models. Aims. We characterize the dust emission from 179 disks in the core of the young (0.5 Myr) NGC 2024 cluster. By studying how the disk mass varies within the cluster, and comparing these disks to those in other regions, we aim to determine how external photoevaporation influences disk properties over time. Methods. Using the Atacama Large Millimeter/submillimeter Array, a 2.9′× 2.9′ mosaic centered on NGC 2024 FIR 3 was observed at 225 GHz with a resolution of 0.25″, or ~100 AU. The imaged region contains 179 disks identified at IR wavelengths, seven new disk candidates, and several protostars. Results. The overall detection rate of disks is 32 ± 4%. Few of the disks are resolved, with the exception of a giant (R = 300 AU) transition disk. Serendipitously, we observe a millimeter flare from an X-ray bright young stellar object (YSO), and resolve continuum emission from a Class 0 YSO in the FIR 3 core. Two distinct disk populations are present: a more massive one in the east, along the dense molecular ridge hosting the FIR 1-5 YSOs, with a detection rate of 45 ± 7%. In the western population, towards IRS 1, only 15 ± 4% of disks are detected. Conclusions. NGC 2024 hosts two distinct disk populations. Disks along the dense molecular ridge are young (0.2–0.5 Myr) and partly shielded from the far ultraviolet radiation of IRS 2b; their masses are similar to isolated 1–3 Myr old SFRs. The western population is older and at lower extinctions, and may be affected by external photoevaporation from both IRS 1 and IRS 2b. However, it is possible these disks had lower masses to begin with.