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首页> 外文期刊>The Astrophysical journal >LOCATING THE ACCRETION FOOTPRINT ON A HERBIG Ae STAR: MWC 480
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LOCATING THE ACCRETION FOOTPRINT ON A HERBIG Ae STAR: MWC 480

机译:在草药Ae星星上找到累积足迹:MWC 480

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Accretion is a fundamental process which establishes the dynamics of the protoplanetary disk and the final properties of the forming star. In solar-type stars, the star-disk coupling is determined by the magnetic field structure, which is responsible for funneling material from the disk midplane to higher latitudes on the star. Here, we use pan-chromatic data for the Herbig Ae star MWC 480 to address whether similar processes occur in intermediate-mass stars. MWC 480 has X-ray emission typical of actively accreting Herbig Ae stars, but with ~10× more photoelectric absorption than expected from optical and FUV data. We consider three sources for the absorption: the disk, absorption in a wind or jet, and accretion. While we detect the disk in scattered light in a re-analysis of archival Hubble Space Telescope data, the data are consistent with grazing illumination of the dust disk. We find that MWC 480's disk is stratified, geometrically thin, and is not responsible for the observed photoelectric absorption. MWC 480 drives a bipolar jet, but with a mass-loss rate that is low compared to other Herbig Ae stars, where the outflow is more favorably oriented and enhanced photoelectric absorption is not seen. This excludes a jet or wind origin for the enhanced photoelectric absorption. We compare MWC 480's O VI emission with other Herbig Ae stars. The distribution of the emission in inclination, and lack of a correlation of profile shape and system inclination excludes equatorially confined accretion for the FUSE Herbig Ae stars. The photoelectric absorption data further suggest that the accretion footprint on MWC 480 and other Herbig Ae stars is located at high-temperate, rather than polar, latitudes. These findings support the presence of funneled accretion in MWC 480 and Herbig Ae stars, strengthening the parallel to T Tauri stars.
机译:吸积是建立原行星盘动力学和恒星最终特性的基本过程。在太阳型恒星中,星盘耦合是由磁场结构决定的,磁场的作用是使材料从盘中平面漏斗到恒星的更高纬度。在这里,我们使用Herbig Ae恒星MWC 480的全色数据来解决中等质量恒星中是否发生了类似的过程。 MWC 480具有主动吸收Herbig Ae恒星的典型X射线发射,但比光学和FUV数据预期的吸收光强约10倍。我们考虑了三个吸收源:圆盘,风或射流吸收和吸积。在重新分析档案哈勃太空望远镜的数据时,虽然我们在散射光下检测到磁盘,但这些数据与尘埃盘的掠射照明一致。我们发现MWC 480的磁盘是分层的,几何形状较薄,并且与观察到的光电吸收无关。 MWC 480驱动双极射流,但质量损失率比其他Herbig Ae星低,后者的流出方向更有利,并且看不到增强的光电吸收。这不包括用于增强光电吸收的射流或风源。我们将MWC 480的O VI发射与其他Herbig Ae恒星进行了比较。发射的倾斜度分布以及轮廓形状和系统倾斜度的相关性均不包括FUSE Herbig Ae星的赤道限定积积。光电吸收数据进一步表明,MWC 480和其他Herbig Ae恒星上的积聚足迹位于高温而非纬度。这些发现支持在MWC 480和Herbig Ae星中存在漏斗状积聚,从而加强了与T Tauri星的平行度。
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