Heating and Ionization of X-Winds
Heating and Ionization of X-Winds
复制标题
X-Winds 的加热和电离
DOI：
10.1086/324197
复制
发表时间：
2001
期刊：
影响因子：
--
通讯作者：
S. Lizano
中科院分区：
文献类型：
--
作者：
H. Shang;A. Glassgold;F. Shu;S. Lizano
为了将x风与观测结果进行比较，人们需要能够计算出它的热和电离特性。我们建立了稳定x风的电离方程和热方程逐流线积分的物理基础。除了众所周知的与恒星和吸积漏斗热点辐射与风的相互作用有关的过程外，我们还包括x射线加热和电离，机械加热和修正的双极扩散加热计算。机械加热是由随时间变化的x风的星盘相互作用产生的波动引起的，这些波动被风带到很远的地方，在那里它们以激波、MHD波和湍流级联的形式消散。我们用无标度体积加热速率Γmech = αρv3s-1来模拟时间平均加热，其中ρ和v分别是局部质量密度和风速，s是到原点的距离，α是一个现象常数。当我们考虑一个部分显示但活跃的年轻恒星物体时，我们发现在我们的数值计算中选择α ~ 10-3会产生足够高的温度和电子分数，使x风射流在观测到的水平和空间尺度上的光学禁线中辐射。我们还讨论了热化学计算的各种应用，这些应用可以导致对x风理论的进一步观测检查。
In order to compare the X-wind with observations, one needs to be able to calculate its thermal and ionization properties. We formulate the physical basis for the streamline-by-streamline integration of the ionization and heat equations of the steady X-wind. In addition to the well-known processes associated with the interaction of stellar and accretion funnel hot spot radiation with the wind, we include X-ray heating and ionization, mechanical heating, and a revised calculation of ambipolar diffusion heating. The mechanical heating arises from fluctuations produced by star-disk interactions of the time-dependent X-wind that are carried by the wind to large distances where they are dissipated in shocks, MHD waves, and turbulent cascades. We model the time-averaged heating by the scale-free volumetric heating rate, Γmech = αρv3s-1, where ρ and v are the local mass density and wind speed, respectively, s is the distance from the origin, and α is a phenomenological constant. When we consider a partially revealed but active young stellar object, we find that choosing α ~ 10-3 in our numerical calculations produces temperatures and electron fractions that are high enough for the X-wind jet to radiate in the optical forbidden lines at the level and on the spatial scales that are observed. We also discuss a variety of applications of our thermal-chemical calculations that can lead to further observational checks of X-wind theory.
影响因子：
3.2
作者：
V. Mannings;A. Boss;S. Russell
通讯作者：
V. Mannings;A. Boss;S. Russell