arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1201.3577astro-ph.SR
收藏

原行星盘中的阴影、间隙和环状结构

Shadows, gaps, and ring-like structures in protoplanetary disks

Ralf Siebenmorgen, Frank Heymann

摘要:

研究了Tauri T星和Herbig Ae星周围被动加热盘的结构,提出了一个矢量化的原行星盘尘埃辐射转移模型。与标量版本的代码相比,矢量化提供了100的加速因子。尘埃由蓬松的碳和各种大小的硅酸盐颗粒或弥漫的ISM尘埃组成。由MC方法得到的红外发射和中平面温度不同于其中辐射转移在小环段的平板几何形状中求解的模型。在MC处理,尘埃晕以上的磁盘被认为是。晕导致增强的红外发射和温暖的中平面温度比纯磁盘。在流体静力平衡的假设下,我们发现,在内部边缘的磁盘鼓起,其次是阴影区。阴影降低了中板的温度,并降低了盘的消光层的高度。它可以被看作是圆盘中的一个缺口,除非它的表面再次暴露在直接的恒星辐射中。在那里,圆盘第二次膨胀,第三次膨胀,如此类推。因此,几个间隙和环状结构存在于磁盘表面,并出现在发射图像。它们是由圆盘中的阴影产生的,并且不需要假设任何伴星或行星的存在。与赫比格Ae型恒星相比,这种间隙和环状结构在金牛座T型恒星周围的类地行星区域更为明显。

英文摘要:

We study the structure of passively heated disks around T Tauri and Herbig Ae stars, and present a vectorized Monte Carlo dust radiative transfer model of protoplanetary disks. The vectorization provides a speed up factor of 100 when compared to a scalar version of the code. Disks are composed of either fluffy carbon and silicate grains of various sizes or dust of the diffuse ISM. The IR emission and the midplane temperature derived by the MC method differ from models where the radiative transfer is solved in slab geometry of small ring segments. In the MC treatment, dusty halos above the disks are considered. Halos lead to an enhanced IR emission and warmer midplane temperature than do pure disks. Under the assumption of hydrostatic equilibrium we find that the disk in the inner rim puffs up, followed by a shadowed region. The shadow reduces the temperature of the midplane and decreases the height of the extinction layer of the disk. It can be seen as a gap in the disk unless the surface is again exposed to direct stellar radiation. There the disk puffs up a second time, a third time and so forth. Therefore several gaps and ring-like structures are present in the disk surface and appear in emission images. They result from shadows in the disks and are present without the need to postulate the existence of any companion or planet. As compared to Herbig Ae stars, such gaps and ring-like structures are more pronounced in regions of terrestrial planets around T Tauri stars.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑