We present Atacama Large Millimeter Array (ALMA) observations at an angular resolution of 0.1-0.2" of the disk surrounding the young Herbig Ae star MWC 758. The data consist of images of the dust continuum emission recorded at 0.88 millimeter, as well as images of the 13CO and C18O J = 3-2 emission lines. The dust continuum emission is characterized by a large cavity of roughly 40 au in radius which might contain a mildly inner warped disk. The outer disk features two bright emission clumps at radii of about 47 and 82 au that present azimuthal extensions and form a double-ring structure. The comparison with radiative transfer models indicates that these two maxima of emission correspond to local increases in the dust surface density of about a factor 2.5 and 6.5 for the south and north clumps, respectively. The optically thick 13CO peak emission, which traces the temperature, and the dust continuum emission, which probes the disk midplane, additionally reveal two spirals previously detected in near-IR at the disk surface. The spirals seen in the dust continuum emission present, however, a slight shift of a few au towards larger radii and one of the spirals crosses the south dust clump. Finally, we present different scenarios in order to explain the complex structure of the disk.
翻译:我们展示了Atacama 大型千米阵列(ALMA)观测,其角分辨率为0.1-0.2”的磁盘围绕年轻的Herbig Ae 明星MWC 758。数据包括记录在0.88毫米时的连续散射图像以及13CO和C18O J = 3-2 排放线的图像。粉尘连续排放的特点是半径大孔状约40au,其中可能包含温和的内温磁盘。外部磁盘在大约47和82au的半射线上有两个亮度的发射芯块,显示的是Azimuthal扩展和形成双环结构。与辐射传导模型的比较表明,这两种最大排放峰值与南部和北部的灰色表面密度约2.5和6.5个系数的局部增加相对。光重的13CO峰值排放以光度为特征,其中记录着温度,以及探测磁盘中平面的灰质连续排放物,还揭示了先前在磁盘表面检测到的两种螺旋螺旋。在目前的磁盘结构中看到的螺旋状状状状状状结构中,最后是向南部的一个微变化。