摘要
The water maser emission from the unusual supergiant,VY CMa,has been observed with the Urumqi 25 m radio telescope.A simple red-shifted maser spectrum was detected in the 1.6 Jy noise level during our monitoring observations.All of the H2O maser features are red-shifted with respect to the VY CMa stellar velocity of 17.6 km.s-1.The spectrum appears to be consisted of two striking like groups and each group has three features.The appearances and the ratio of these three features in the two maser groups are very similar.The H2O maser emission arises from a region close to the supergiant,about 10 stellar radii of the star.The simple red-shifted spectrum could be due to infall masing gas on the near side of the disk.Pulsation of the central star causes oscillations in this portion of the envelope,with shock wave propagating outward and with material falling inward.The masing gas motions are very complex,by which the dramatic changes or the quasi-sinusoidal fluctuation in flux may be explained.
作者
加尔肯 叶生别克
郑兴武
JARKEN Esimbek;ZHENG Xing-Wu(Urumqi Astronomical Observatory,Chinese Academy of Sciences,Urumqi 830011;Department of Astronomy,Nanjing University,Nanjing 210093;Harvard-Smithsonian Center for Astrophysics,60 Garden Street,Cambridge,Massachusetts 02138,USA)
基金
Supported by the National Natural Science Foundation of China under Grant No.10073004.
