<p><a href="https://en.wikipedia.org/wiki/Kapteyn%27s_Star" rel="nofollow noreferrer">Kapteyn's star</a> has 14% the metallicity of the Sun and is about 11 billion years old and is in the galactic halo. It has two reported planets.</p>
<p>I don't know if 14% is low enough to count as  Population II, but according to the NASA exoplanet archive it is the lowest metallicity star known to have planets.</p>

CC BY-SA 4.0
2020-02-26T20:20:05.163Z
I seem to recall that below $[Fe/H] \approx -0.3$ stars count as Pop II, so that would include Kapteyn's star.
AtmosphericPrisonEscape
CC BY-SA 4.0
2020-02-26T20:56:33.320Z
Its not particularly metal-poor. There is no strict definition, but this would be a borderline case. It is not in the halo, it is only 12 light years from Earth.
ProfRob
CC BY-SA 4.0
2020-02-26T21:14:09.313Z
According to the article https://academic.oup.com/mnras/article/350/2/575/1117003 it is a halo star.
sno
CC BY-SA 4.0
2020-02-26T21:48:54.360Z
It's kinematically a halo star, but is isn't "in the halo". Pedantic possibly, but a lot of readers would misunderstand. The same reference also provides a lower metallicity than your value.
ProfRob
CC BY-SA 4.0
2020-02-26T18:42:32.220Z
2021-05-11T06:40:16.540Z
2021-05-11T06:40:16.540Z
sno
<p>I always understood that Population II stars were unlikely to have planets as they were virtually all H and He with very little else.</p>

<p>Have recent observations confirmed this, or have planets been discovered around Population II stars?</p>

<exoplanet><metallicity>
Have any planetary systems been found around Population II stars?
Mike Stone
# Have any planetary systems been found around Population II stars?

(Asked by: username_0 on 2020-02-26)

I always understood that Population II stars were unlikely to have planets as they were virtually all H and He with very little else.

Have recent observations confirmed this, or have planets been discovered around Population II stars?

**Tags:** exoplanet, metallicity

---

## 1 answers

### Answer by username_1 on 2020-02-26. Score: 4

[Kapteyn's star](https://en.wikipedia.org/wiki/Kapteyn%27s_Star) has 14% the metallicity of the Sun and is about 11 billion years old and is in the galactic halo. It has two reported planets.

I don't know if 14% is low enough to count as Population II, but according to the NASA exoplanet archive it is the lowest metallicity star known to have planets.

> **Comments:**
> **username_2**: I seem to recall that below $[Fe/H] \approx -0.3$ stars count as Pop II, so that would include Kapteyn's star.  
> **username_3**: Its not particularly metal-poor. There is no strict definition, but this would be a borderline case. It is not in the halo, it is only 12 light years from Earth.  
> **username_1**: According to the article https://academic.oup.com/mnras/article/350/2/575/1117003 it is a halo star.  
> **username_3**: It's kinematically a halo star, but is isn't "in the halo". Pedantic possibly, but a lot of readers would misunderstand. The same reference also provides a lower metallicity than your value.  

---

