Radiative levitation of silicon in the atmospheres of two Hyades DA white dwarfs
Radiative levitation of silicon in the atmospheres of two Hyades DA white dwarfs
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两颗毕星 DA 白矮星大气中硅的辐射悬浮
DOI：
10.1093/mnrasl/slt149
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发表时间：
2013
影响因子：
4.8
通讯作者：
P. Chayer
中科院分区：
文献类型：
--
作者：
P. Chayer
在两颗毕宿二DA白色矮星WD 0421+162和WD 0431+126的表面存在硅元素，需要有机制来抵消向下扩散的影响。辐射悬浮计算表明，在WD 0431+126中观察到的硅丰度对应于辐射悬浮支持的丰度。考虑到辐射悬浮和吸积的详细的随时间变化的扩散计算表明，dM/dt（Si）< 1.00E4 g/s的吸积也可能存在，而不会破坏辐射悬浮所支持的丰度。在WD 0421+162的情况下，必须以dM/dt（Si）= 1.25E5 g/s的速率进行吸积，因为其观测到的硅丰度大于辐射悬浮支持的丰度。这个吸积速率低于吸积-扩散模型给出的吸积速率，因为辐射悬浮减慢了硅的向下扩散。在两颗毕宿白色矮星中观测到的硅丰度不能仅仅用吸积来解释。对硅丰度的解释必须考虑到辐射悬浮和吸积之间的相互作用。
The presence of silicon at the surface of the two Hyades DA white dwarfs WD 0421+162 and WD 0431+126 requires mechanisms that counteract the effects of the downward diffusion. Radiative levitation calculations indicate that the silicon abundance observed in WD 0431+126 corresponds to the abundance supported by radiative levitation. Detailed time-dependent diffusion calculations that take into account radiative levitation and accretion indicate that accretion with rates of dM/dt(Si) < 1.00E4 g/s could also be present without disrupting the abundance supported by radiative levitation. In the case of WD 0421+162, accretion with a rate of dM/dt(Si) = 1.25E5 g/s must be invoked, because its observed silicon abundance is larger than the abundance supported by radiative levitation. This accretion rate is lower than the accretion rate given by the accretion-diffusion model, because the radiative levitation slows down the downward diffusion of silicon. The silicon abundances observed in the two Hyades white dwarfs cannot be interpreted solely in terms of accretion. The interpretation of the silicon abundances must take into account the interplay between radiative levitation and accretion.
虚拟天文台服务TheoSSA：建立OB型亚矮星Feige 110的合成恒星通量标准II NLTE光谱分析数据库
影响因子：
6.5
作者：
Rudkowski;Kampka;Werner;Moehler
通讯作者：
Moehler