Recent content by Galaxy111

Good point Vanadium; especially your no. 1 seems to lead to this suggestion. My initial thinking was also stellar dynamics, as it will convince as well. But still, from the pure pure spectrum shift it seems to be quite difficult, if anyhow possible, to tell its the moving envelope. Thanks...

Yes - thank you Chronos. I know these calculations. Only, it doesn't really explain the tricky question. Why can we tell from the pure Doppler-shift of the Cepheid spectrum that the envelope of the star is moving and the red/blue-shift doesn't have some other cause? Interesting though. I think...

Thanks for an answer mgb phys. Yes, in fact all of the three have well to be considered. Cheers Galaxy

Hi all, Recently I came across an interesting question: "...Why do astronomers attribute the observed Doppler shifts of a Cepheid variable as pulsation, rather than to some other causes, such as orbital motion? " OK, I have my ideas about the problem as there is a correlation between e...