Hello space fans,

         Does Arcturus move against the Galactic tide so-to-speak ?

Is Arcturus considered a rogue star travelling "thru" the Milky Way ?

Thanks

Misunderstood the question - sorry 'bout that.

George

Arcturus has a velocity relative to our sun that is higher than other bright stars. Compared with the set of surrounding stars- which orbit our galaxy in more or less circular orbits- it falls behind by about 100 kps (as do several others of the 'Arcturus Group'). This lagging movement has long suggested that the star comes from an older population of the Milky Way.

Rogue perhaps, but certainly in no hurry.

SJS 

I read in one book that Arcturus is yellow.  I read in another that it is orange.  I think it is orange. 

It's an orange, K1 giant with a surface temperature of 4300K. However, it looks yellow to me.

Here's a simple spectrogram I made using a diffraction grating and a DSLR:

which shows it to be predominantly yellow (at least to a detector that's color-balanced to match human eyesight. The little dot at far right is the zeroth-order spectrum (the undiffracted image of the star itself.)

Arcturus is an old star that may be part of the galaxy's thick disk, while the Sun lies within the thin disk.

http://www.solstation.com/stars2/arcturus.htm

Dave Mitsky

Arcturus is an incredibly large star.  You can see its size compared to the size of our sun in this video...

 http://youtube.com/watch?v=HKPUYZZbWxs