论文标题
AGB风向相互作用区域中的灰尘
Dust in AGB wind-ISM interaction regions
论文作者
论文摘要
我们旨在限制恒星风与渐近巨型分支星周周围的恒星风与ISM之间的相互作用区域中的灰尘质量和晶粒尺寸。通过描述这些地区的灰尘，我们旨在阐明低质量进化的恒星在星系中灰尘起源中的作用。我们在70微米和160微米的远红外中使用图像来得出在富含碳和富氧的渐近巨型巨型分支（AGB）恒星样品周围的风向相互作用区域中的灰尘温度和尘埃质量。尘埃温度和质量以两种方式确定。首先，使用测量通量的比率直接从数据中，并假设恒定晶粒尺寸为0.1微米的灰尘。然后，我们执行3D尘埃转移模型，在空间上受到观测的限制，以始终如一地计算温度和质量。对于辐射转移模型，每个模型都包含一个恒定的晶粒尺寸，在0.01微米至5.0微米之间变化。我们发现，风向相互作用区域中观察到的尘埃质量与恒星风中积累的质量一致。对于富含碳的资源，在辐射转移模型中添加空间约束的来源会导致优先更大的晶粒尺寸（约2微米）。对于富氧的来源，空间约束导致模型中的温度过高，因此无法拟合所观察到的远红外比例，而与所使用的晶粒尺寸无关，表明晶粒特性和恒星辐射场的相互作用更为复杂。结果对谷物的过渡到ISM的过渡以及后来充当ISM颗粒生长的种子的性质有影响。但是，富氧来源的结果表明，灰尘特性的推导不是直接的，需要更复杂的建模
We aim to constrain the dust mass and grain sizes in the interaction regions between the stellar winds and the ISM around asymptotic giant branch stars. By describing the dust in these regions, we aim to shed light on the role of low mass evolved stars in the origin of dust in galaxies. We use images in the far-infrared at 70 micron and 160 micron to derive dust temperatures and dust masses in the wind-ISM interaction regions around a sample of carbon-rich and oxygen-rich asymptotic giant branch (AGB) stars. The dust temperature and mass are determined in two ways. First directly from the data using the ratio of the measured fluxes and assuming opacities for dust with a constant grain size of 0.1 micron. We then perform 3D dust-radiative transfer models spatially constrained by the observations to consistently calculate the temperature and mass. For the radiative transfer models each model contains one constant grain size, which is varied between 0.01 micron to 5.0 micron. We find that the observed dust mass in the wind-ISM interaction regions is consistent with mass accumulated from the stellar winds. For the carbon-rich sources adding the spatial constraints in the radiative transfer models results in preferentially larger grain sizes (approx. 2 micron). For the oxygen-rich sources the spatial constraints result in too high temperatures in the models, making it impossible to fit the observed far-infrared ratio irrespective of the grain size used, indicating a more complex interplay of grain properties and the stellar radiation field. The results have implications for how likely it is for the grains to survive the transition into the ISM, and the properties of dust particles that later act as seeds for grain growth in the ISM. However, the results for the oxygen-rich sources show that the derivation of dust properties is not straight forward, requiring more complex modelling
