Dust masses of young disks: constraining the initial solid reservoir for planet formation
Dust masses of young disks: constraining the initial solid reservoir for planet formation
复制标题
DOI：
10.1051/0004-6361/202037851
复制
发表时间：
2020-06
影响因子：
6.5
通讯作者：
Ł. Tychoniec;C. Manara;G. Rosotti;E. V. van Dishoeck;A. Cridland;T. Hsieh;N. Murillo;D. Segura-Cox-D.-Se
中科院分区：
文献类型：
--
作者：
Ł. Tychoniec;C. Manara;G. Rosotti;E. V. van Dishoeck;A. Cridland;T. Hsieh;N. Murillo;D. Segura-Cox-D.-Se
形成行星的初始物质库是什么？当II类盘（1-3百万年）的测量质量被发现始终小于气体巨星核心形成所需的质量时，行星形成的这个关键问题变得更加相关。解决这个难题的一个方法是调查年轻阶段的磁盘是否包含足够的灰尘。如果行星形成得更早，在最初的0.5百万年，我们利用阿塔卡玛大型毫米/亚毫米阵（阿尔马）和现有的甚大阵（VLA）对英仙座分子云中的嵌入盘进行了观测数据提供一个强大的估计磁盘质量和比较英仙座调查的尘埃质量与其他阿尔马调查的年轻和成熟的磁盘。在不同波长下观测的两个干涉测量设施的组合使得能够详细描述年轻磁盘的尘埃排放。我们对尘埃盘质量中位数的最佳估计是158 M（地球质量）和50 M，分别为0级和I级。这些值远高于II类椎间盘中常见的中值（约5 M）（图1）。在图2中，我们表明，通常在系外行星系统中发现的质量在0类和I类中的质量范围内。我们将改进的盘质量估计放在已知系外行星系统质量的背景下。英仙座0级和I级盘的质量可以产生所观察到的系外行星系统，其效率可以被行星形成模型所接受。观测到的最大质量的系外行星仍然可以由最大质量的0级盘产生，效率为15%，如果行星形成开始于I级盘，则需要30%的更高效率。有趣的是，我们发现大多数大型系外行星系统需要更高的效率。(Fig.我们的结果与行星形成的起点已经处于0级阶段最为一致，即星星和盘形成过程开始后的第一个0.1百万年。这对太阳系外行星和我们太阳系形成的物理和化学条件有着重要的影响。系外行星尘埃盘质量和固体含量的累积分布函数。上图：使用阿尔马测量的英仙座0类（红色）和I类（蓝色）盘以及狼疮II类盘（黄色）尘埃质量的累积分布函数（Ansdell等人，2016）。在黑色中，系外行星系统的质量被归一化为气态行星的比例（Cumming et al. 2008）。英仙座盘质量计算与9毫米=0.28厘米2克1从VLA通量。中位数在标签中注明。底部：放大到系外行星存在的范围。颜色刻度显示了行星形成所需的效率，对于给定的分布箱。图2。图中显示了从exoplanet.eu目录（Schneider et al. 2011）中获得的系外行星系统的质量分布，这些系外行星系统围绕着具有测量质量的主序星。阴影区域标记的范围，我们最好的估计尘埃盘质量英仙座：0级（红色）和I级（蓝色）计算的VLA通量与不透明度值为9毫米=0.28厘米2克1。0类和I类的分布中位数分别为158和52 M，用虚线表示。狼疮3 M中II类椎间盘的中位质量（Ansdell et al. 2016）以黄色显示。系外行星系统中固体的质量与宿主星星的质量成比例。所有有质量信息的行星都包含在这张图中。
What is the initial reservoir of mass available for making planets? This key question for planet formation got even more relevant when the measured masses of the Class II disks (1-3 Myr old) were found consistently smaller than what is needed for the formation of gas giant cores. One way to solve this conundrum is to investigate whether the disks at the younger stages contain enough dust. Should planets be formed earlier, in the first 0.5 Myr, the physical conditions and chemical composition assumed of the beginning of planet formation needs to be revised.We use Atacama Large Millimeter/submillimeter Array (ALMA) observations of embedded disks in Perseus molecular cloud together with existing Very Large Array (VLA) data to provide a robust estimate of disk masses and to compare the Perseus survey of dust masses with other ALMA surveys of young and mature disks. The combination of the two interferometric facilities observing at different wavelengths enables detailed characterization of the dust emission from young disks. Our best estimate of the median dust disk masses is 158 M⊕ (Earth masses) and 50 M⊕, for Class 0 and Class I respectively. These values are much higher than the median found typically in Class II disks (~5 M⊕) (Fig. 1). In Fig. 2 we show that the masses typically found in exoplanetary systems are well in a range of masses available in Class 0 and Class I.We put the improved disk mass estimates in the context of masses of known exoplanetary systems. The masses of Class 0 and I disks in Perseus can produce the observed exoplanet systems with efficiencies acceptable by planet formation models. The most massive observed exoplanets can still be produced by the most massive Class 0 disks with an efficiency of 15%, higher efficiencies on the order of 30% are needed if the planet formation starts in Class I. Interestingly, we find that most massive exoplanetary systems require higher efficiencies. (Fig. 1, right).Our results are most consistent with the starting point of the planet formation already in the Class 0 stage, first 0.1 Myr after the beginning of the star and disk formation process. This has major implications for the physical and chemical conditions of the formation of extrasolar planets and of our own Solar System.Fig. 1. Cumulative distribution function of dust disk masses and solid content of exoplanets. Top: Cumulative distribution function of dust masses for Class 0 (red) and Class I (blue) disks in Perseus and Class II disks (yellow) in Lupus measured with ALMA (Ansdell et al. 2016). In black, the masses of the exoplanet systems are normalized to the fraction of the gaseous planets (Cumming et al. 2008). Perseus disk masses calculated with κ9mm=0.28 cm2g−1 from the VLA fluxes. Medians are indicated in the labels. Bottom: Zoom-in to the ranges where exoplanets are present. The color scale shows the efficiency needed for the planet formation for a given bin of the distribution.Fig. 2. Plot showing the distribution of masses of exoplanetary systems obtained from the exoplanet.eu catalog (Schneider et al. 2011), for planets around main-sequence stars with the measured masses. Shaded areas mark the range of our best estimation of the dust disk masses in Perseus: Class 0 (red) and Class I (blue) calculated from the VLA fluxes with the opacity value of κ9mm=0.28 cm2g−1. Medians of the distributions, 158 and 52 M⊕, for Class 0 and I, respectively, are indicated with the dashed lines. The median mass of the Class II disks in Lupus, 3 M⊕ (Ansdell et al. 2016) is shown in yellow. The masses of the solids in exoplanetary systems are plotted against the stellar mass of the host star. All planets with available information on the mass are included in this plot.