Dust Hot Spots at 10 au Scales around the Class 0 Binary IRAS 16293–2422 A: A Departure from the Passive Irradiation Model
Dust Hot Spots at 10 au Scales around the Class 0 Binary IRAS 16293–2422 A: A Departure from the Passive Irradiation Model
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DOI：
10.3847/2041-8213/aca53a
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发表时间：
2022-12
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通讯作者：
M. Maureira;M. Gong;J. Pineda;H. Liu;Kedron Silsbee;P. Caselli;J. Zamponi;D. Segura-Cox;A. Schmiedeke
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作者：
M. Maureira;M. Gong;J. Pineda;H. Liu;Kedron Silsbee;P. Caselli;J. Zamponi;D. Segura-Cox;A. Schmiedeke
描述0类源在盘尺度上的物理条件对于约束原恒星吸积过程和行星形成的初始条件至关重要。我们使用阿尔马1.3和3毫米的观测，调查周围的尘埃的物理条件的0类二进制IRAS 16293-2422 A下降到100 Au尺度。环双星物质的光谱指数α的中位数为3.1，色散为0.2，没有确凿的证据表明其中存在毫米级的颗粒。在两个波长下，在圆盘附近观察到具有T B = 60-80 K在1.3 mm处的亮度温度峰值的连续体子结构。这些峰值与α的强烈变化不重叠，表明它们跟踪高温点，而不是具有显著光学深度变化的区域。在热点中推断的尘埃温度的下限为122、87和49 K。根据假定的尘埃不透明度指数，这些值可能会高出几倍。它们与高气体温度和增强的复杂有机分子发射重叠。这个新解决的尘埃温度分布是在更好地符合机械，而不是最常见的假设辐射加热的期望。特别是，我们发现，温度与冲击加热的预测。这一证据和最近的研究强调吸积加热0类磁盘表明，机械加热（冲击，耗散吸积供电等）。是重要的，在早期阶段，应考虑建模和测量深埋原恒星和磁盘的属性。
Characterizing the physical conditions at disk scales in class 0 sources is crucial for constraining the protostellar accretion process and the initial conditions for planet formation. We use ALMA 1.3 and 3 mm observations to investigate the physical conditions of the dust around the class 0 binary IRAS 16293–2422 A down to ∼10 au scales. The circumbinary material’s spectral index, α, has a median of 3.1 and a dispersion of ∼0.2, providing no firm evidence of millimeter-sized grains therein. Continuum substructures with brightness temperature peaks of T b ∼ 60–80 K at 1.3 mm are observed near the disks at both wavelengths. These peaks do not overlap with strong variations of α, indicating that they trace high-temperature spots instead of regions with significant optical depth variations. The lower limits to the inferred dust temperature in the hot spots are 122, 87, and 49 K. Depending on the assumed dust opacity index, these values can be several times higher. They overlap with high gas temperatures and enhanced complex organic molecular emission. This newly resolved dust temperature distribution is in better agreement with the expectations from mechanical instead of the most commonly assumed radiative heating. In particular, we find that the temperatures agree with shock heating predictions. This evidence and recent studies highlighting accretion heating in class 0 disks suggest that mechanical heating (shocks, dissipation powered by accretion, etc.) is important during the early stages and should be considered when modeling and measuring properties of deeply embedded protostars and disks.