Sirius

[cosmo]

Hi !

I have 3 questions:

I read in an other thread that the star Sirius in older times was coppery colored or red. In modern times it's now blue.

1) When did yhe change occure ?

2)Sirius is a dubbelstar, has the change of color something to do with that ?

3)Are the two stars of the same age and color?

[Skulled]

The Sirius is a binary system, with the individual stars given the name Sirius A and Sirius B. The star we can observe is Sirius B, which is an O classified star.

The companion Sirius A is a white dwarf with a much lesser magnitude and it is quite difficult to observe due to the magnitude of Sirius B. The color of Sirius B has nothing to do with the binary system on the large scale, its color is primarily due to its temperature.

And the two stars are not of the same age and color.

Hope this helps.

[timeshifter]

another possible explanation: dopplar effect.

If it looks blue, it may be coming towards us.

If it looks red, it may be going away from us.

temperature has no effect on the dopplar effect, and visa versa.