<p>If they are both in the Gaia DR2 catalogue, then a physical binary should have components with similar parallax and proper motion.</p>

CC BY-SA 4.0
2019-02-23T23:01:40.930Z
2019-02-23T23:01:40.930Z
ProfRob
<p>I have list of stellar pairs from The Washington Double Star Catalog (WDS), i.e. I have next parameters:</p>

<ul>
<li>angular separations</li>
<li>position angles</li>
<li>stellar magnitudes of both components</li>
</ul>

<p>Additionally I have GAIA DR2 parallaxes (and other parameters) from SIMBAD database. How to distinguish between binary and optical stellar pairs? </p>

<gravity><binary-star>
How to separate binary and optical stellar pairs?
user2579566
# How to separate binary and optical stellar pairs?

(Asked by: username_0 on 2019-02-23)

I have list of stellar pairs from The Washington Double Star Catalog (WDS), i.e. I have next parameters:

* angular separations
* position angles
* stellar magnitudes of both components

Additionally I have GAIA DR2 parallaxes (and other parameters) from SIMBAD database. How to distinguish between binary and optical stellar pairs?

**Tags:** gravity, binary-star


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## 1 answers

### Answer by username_1 on 2019-02-23. Score: 2

If they are both in the Gaia DR2 catalogue, then a physical binary should have components with similar parallax and proper motion.


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