Canis Majoris

[CedrikG]

Hi folks !

Quick question. Canis majoris in Stellarium is said to be 1120 light years away. On Wikipedia it says 3900 light years. I mean .. thats a few kilometers of difference. Which one is more accurate in your opinion ?

Thanks guys

[ronin]

One will be lightyears the other will be parsec's.

1 lightyear = 0.3066 parsec approx.

So 3900 Ly = 1195 Pc

There will be a spread of distance values as every so often someone comes up with a "better" measurement of distance and it take a while for any update to filter through if it does filter through.

[Stu]

Other way round Ronin.

1 parsec = 3.26 light years

[Stu]

SkySafari shows Sirius as 2.63 parsecs (pc) or 8.58 light years which is the closest in the constellation but all the others are much further away, and at varying distances

[CedrikG]

I mean the Canis Majoris star, the red giant. In my stellarium program it says 1120 light years, not parsecs. Then I went on Wiki to know more about the star, and it really says 3.900 light years.  I made sure at first I was not mistaking with Kiloparsecs and LY.

[Stu]

Can you post the link to Wiki? Canis Major is the constellation, which star are you referring to?

[CedrikG]

Wikipedia link
http://en.wikipedia.org/wiki/VY_Canis_Majoris

Screen shot of my stellarium
 

[Stu]

Ahh, that's the confusion, the star is VY Canis Majoris, not just Canis Majoris.

Let me have a look and come back to you...

[Stu]

Hi

It looks like you've got the wrong star selected in Stellarium, it should be HIP 35793, not 33856.

There may still be some variation but see what it says for that

[CedrikG]

Sorry for some reason the screen shot was not showing the star, heres a better one
 

[CedrikG]

Oh wow, yes you are right ! There was that very faint red giant a bit over!

You learned me about the identification of the star, HIP *****. Thanks ! That will help a lot.

[CedrikG]

For those who might be interest