GW Ori：三重系统中的内部磁盘重新调整
GW Ori: Inner disk readjustments in a triple system
摘要：
我们利用高分辨率光谱和$U$波段测光研究了年轻恒星系统GWOri的吸积/风活动。我们还通过模拟其光谱能量分布（SED）来表征GW Ori的盘属性。通过比较我们的数据的合成光谱，我们分类GW猎户座作为一个G8星。基于从光谱中得到的RV，我们确认了先前的结果，即GW Ori中的近伴星，周期约为242天，轨道半长轴约为1 AU。用轨道解减去吸积相关发射线的等效宽度后的RV残差在短时间间隔内以5-6.7天的周期变化，这是由旋转调制引起的。GW Ori的H $α$和H $β$谱线轮廓可以分解为两个中心峰发射分量和一个蓝移吸收分量。吸收分量是由于受到近伴星轨道运动调制的盘风。因此，像GW Ori这样的系统可以用来研究盘风的范围。我们发现GW Ori的吸积速率是相当恒定的，但偶尔可以增强2-3倍。我们使用带隙大小约为25-55 AU的圆盘模型再现了GW Ori的SED。间隙内的一小部分微小尘埃粒子产生了近红外波段的过量发射和10 $μ$ m处强烈而尖锐的硅酸盐特征。在近红外波段，奥利GW的SED在~20年的时间尺度上表现出剧烈的变化，这可以解释为间隙中小尘埃颗粒的数量和分布的变化。我们收集了一个样本的二进制/多个系统的磁盘在文献中，并发现它们的间隙大小和分离的主要伙伴，这是从理论上的预测基本一致的正相关关系。
英文摘要：
(abridged) We study the young stellar system GW Ori, concentrating on its accretion/wind activity by using our high-resolution optical spectra and $U$-band photometry. We also characterize the disk properties of GW Ori by modeling its spectral energy distribution (SED). By comparing our data to the synthetical spectra, we classify GW Ori as a G8 star. Based on the RVs derived from the spectra, we confirm the previous result as a close companion in GW Ori with a period of ~242 days and an orbital semi-major axis of ~1 AU. The RV residuals after the subtraction of the orbital solution with the equivalent widths of accretion-related emission lines vary with periods of 5-6.7 days during short time intervals, which are caused by the rotational modulation. The H$α$ and H$β$ line profiles of GW Ori can be decomposed in two central-peaked emission components and one blue-shifted absorption component. The absorption components are due to a disk wind modulated by the orbital motion of the close companion. Therefore, the systems like GW Ori can be used to study the extent of disk winds. We find that the accretion rates of GW Ori are rather constant but can occasionally be enhanced by a factor of 2-3. We reproduce the SED of GW Ori by using disk models with gaps ~25-55 AU in size. A small population of tiny dust particles within the gap produces the excess emission at near-infrared bands and the strong and sharp silicate feature at 10 $μ$m. The SED of GW Ori exhibits dramatic changes on timescales of ~20 yr in the near-infrared bands, which can be explained as the change in the amount and distribution of small dust grains in the gap. We collect a sample of binary/multiple systems with disks in the literature and find a strong positive correlation between their gap sizes and separations from the primaries to companions, which is generally consistent with the prediction from the theory.
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