<p>From Sirius A to Sirius B on the sky is around 3 arcsec on average.</p>

<p>The separation between Sirius A and Sirius B actually varies from 3 to 11 arcseconds b/c of their orbital motion over a long period of time (<a href="https://florin.myip.org/blog/how-see-sirius-b" rel="nofollow noreferrer">Here</a>). </p>

<p>I believe you're referring to that. There's a lot of information (and even some graphs and diagrams) here: <a href="http://www.as.utexas.edu/white_dwarfs/wkshp_05/SiriusAB.pdf" rel="nofollow noreferrer">Here</a>. The information on that website is sort of vague, but I think it'll be helpful in visualization.</p>

<p>Hope that helps!</p>

CC BY-SA 4.0
2018-10-17T00:40:18.967Z
not the separation between the two, the movement of Sirius A only
pol0
CC BY-SA 4.0
2018-10-17T00:40:41.643Z
Sirius B has a wider orbit
pol0
CC BY-SA 4.0
2018-10-17T01:22:37.147Z
looking at the link you included, http://www.as.utexas.edu/white_dwarfs/wkshp_05/SiriusAB.pdf, it looks like Sirius A has an orbit of 12 arc seconds in total, is that correct?
pol0
CC BY-SA 4.0
2018-10-17T02:21:00.160Z
It looks like so. I think this source is slightly outdated, so I'm not putting too much reliance on it.
MystaryPi
CC BY-SA 4.0
2018-10-17T02:23:26.767Z
I read it wrong actually, it only goes to -0.5, so around 6.5 arc seconds.
pol0
CC BY-SA 4.0
2018-10-17T02:25:02.130Z
Wait... Ha ha looks like I made the same mistake too. The graph goes down to -0.5, so it ranges to 6.5 arcsec. I was looking at the scale and thought that since it goes from -6 to +6 arcseconds, it has a range of 12 arcsec...
MystaryPi
CC BY-SA 4.0
2018-10-17T00:36:17.957Z
2018-10-17T00:36:17.957Z
MystaryPi
<p>I know that Sirius A and B orbit each other. I'd like to ask how large is their relative apparent motion in arc seconds, seen from Earth?</p>

<star-systems>
How many arc seconds is Sirius "spiralling motion" around Sirius B?
pol0
# How many arc seconds is Sirius "spiralling motion" around Sirius B?

(Asked by: username_0 on 2018-10-16)

I know that Sirius A and B orbit each other. I'd like to ask how large is their relative apparent motion in arc seconds, seen from Earth?

**Tags:** star-systems


---

## 1 answers

### Answer by username_1 on 2018-10-17. Score: 1

From Sirius A to Sirius B on the sky is around 3 arcsec on average.

The separation between Sirius A and Sirius B actually varies from 3 to 11 arcseconds b/c of their orbital motion over a long period of time ([Here](https://florin.myip.org/blog/how-see-sirius-b)).

I believe you're referring to that. There's a lot of information (and even some graphs and diagrams) here: [Here](http://www.as.utexas.edu/white_dwarfs/wkshp_05/SiriusAB.pdf). The information on that website is sort of vague, but I think it'll be helpful in visualization.

Hope that helps!

> **Comments:**
> **username_0**: not the separation between the two, the movement of Sirius A only  
> **username_0**: Sirius B has a wider orbit  
> **username_0**: looking at the link you included, http://www.as.utexas.edu/white_dwarfs/wkshp_05/SiriusAB.pdf, it looks like Sirius A has an orbit of 12 arc seconds in total, is that correct?  
> **username_1**: It looks like so. I think this source is slightly outdated, so I'm not putting too much reliance on it.  
> **username_0**: I read it wrong actually, it only goes to -0.5, so around 6.5 arc seconds.  
> **username_1**: Wait... Ha ha looks like I made the same mistake too. The graph goes down to -0.5, so it ranges to 6.5 arcsec. I was looking at the scale and thought that since it goes from -6 to +6 arcseconds, it has a range of 12 arcsec...  

---

