W3(OH)致密HⅡ区磁场研究

本文以W3(OH)为实例,建立了与OH脉泽成协的HII区气体-尘埃壳层的磁场模型,由此可见,致密HII区所在分子云核心中的磁场强度,与分子云核心的分子数密度之间存在指数α=1/2的幂律关系;而在HII区气体-尘埃壳层中,磁场强度与分子数密度之间存在α=1的正比关系,根据讨论可知,与OH脉泽成协的HII区,其气体-尘埃壳层的分子数密度为10~6cm~(-3)量级,磁场强度为几个mG;一旦分子数密度达10~7cm~(-3)量级,OH脉泽便将熄灭。

A Research on Magnetic Fields in the Uttracompact HII Region of W3(OH)

This paper has established a model of structure of magnetic field in gas-dust shell around a HII region associated with OH maser sources. The W3(OH) is a typical example. It is found that the strength of magnetic field is related to themolecular density with a power factor of a = - 1/2 in a molecular cloud core wherethe HII region embeds in, and with a = 1 in the gas-dust shell around HII region. The molecular density is about a few 106 cm-3 and the strength of magnetic field is about a few mG in a HII region associated with OH maser sources. When the molecular density is over 107 cm-3, the OH maser will be quenched.