<p>See nnnnnn's comment below.</p>

<p>The <a href="https://www.nasa.gov/feature/jpl/small-asteroid-or-comet-visits-from-beyond-the-solar-system" rel="nofollow noreferrer">NASA website</a>, describing <a href="https://en.wikipedia.org/wiki/%CA%BBOumuamua" rel="nofollow noreferrer">'oumuamuam</a>, uses the term "interstellar object." Extrasolar asteroid would seem to be another option.  I haven't seen a unique word different from asteroid that originated outside of the solar system.</p>

<p>It seems a simple prefix is sufficient to describe objects beyond the solar system, i.e. exoplanet.</p>

<p>Scienfitic American has an <a href="https://www.scientificamerican.com/article/two-interstellar-intruders-are-upending-astronomy/?utm_source=newsletter&amp;utm_medium=email&amp;utm_campaign=daily-digest&amp;utm_content=link&amp;utm_term=2019-11-27_featured-this-week&amp;spMailingID=61644144&amp;spUserID=MTE1NjM1NDM5MjAwS0&amp;spJobID=1764375774&amp;spReportId=MTc2NDM3NTc3NAS2" rel="nofollow noreferrer">article</a> which uses the term "interstellar object."</p>

<p>Also, see answers to:</p>

<ul>
<li><a href="https://astronomy.stackexchange.com/q/33680/7982">Is intrastellar commonly used by astronomers to refer to objects within our solar system?</a></li>
<li><a href="https://astronomy.stackexchange.com/q/30131/7982">Adjective for things outside our solar system</a></li>
</ul>

CC BY-SA 4.0
2019-12-01T01:39:03.590Z
Isn't *exoplanet* normally used to describe planets that orbit stars other than our Sun? As compared to *rogue planets*, which do not orbit a star.
nnnnnn
CC BY-SA 4.0
2019-12-01T01:46:43.020Z
@nnnnnn Yup, you are right.  You should write that as an answer and not just as a comment.
Bob516
CC BY-SA 4.0
2019-12-01T01:58:29.513Z
Well I don't think it is a complete answer because it doesn't apply to smaller objects. I guess *rogue* could also be applied to asteroids and so forth, but I didn't post an answer because I don't have sources I can quote to back that up.
nnnnnn
CC BY-SA 4.0
2019-11-30T14:13:51.957Z
2019-12-09T00:57:15.773Z
2019-12-09T00:57:15.773Z
Bob516
<p>I'm trying to think of a good word for an asteroid/planetoid that has no stable orbit but has been ejected from a system and is passing close to a sun. Any help?</p>

CC BY-SA 4.0
2019-11-30T14:02:14.977Z
Welcome to Stack Exchange watercollider.  I think your question could be cleaned up a little.  Isn't a planetoid an asteroid?
Bob516
CC BY-SA 4.0
2019-11-30T17:21:52.230Z
Are you looking for an existing alternative or do you want a new one?
Mitch Harris
CC BY-SA 4.0
2019-12-01T23:22:18.277Z
["A rogue planet (also termed an interstellar planet, nomad planet, free-floating planet, unbound planet, orphan planet, wandering planet, starless planet, or sunless planet) is a planetary-mass object that orbits a galactic center directly."](https://en.wikipedia.org/wiki/Rogue_planet)
Keith McClary
CC BY-SA 4.0
2019-12-09T00:51:32.300Z
I'd recommend that you consider their orbits *open, unbound or non-periodic*, but not "unstable". In orbital mechanics "unstable" usually applies only to *closed, bound, and periodic* orbits.
uhoh
<asteroids><terminology>
What are other names for planetoids that aren't orbiting a solar system, but hurtling through space?
watercollider
# What are other names for planetoids that aren't orbiting a solar system, but hurtling through space?

(Asked by: username_0 on 2019-11-30)

I'm trying to think of a good word for an asteroid/planetoid that has no stable orbit but has been ejected from a system and is passing close to a sun. Any help?

**Tags:** asteroids, terminology
> **Comments:**
> **username_1**: Welcome to Stack Exchange watercollider.  I think your question could be cleaned up a little.  Isn't a planetoid an asteroid?  
> **username_2**: Are you looking for an existing alternative or do you want a new one?  
> **username_3**: ["A rogue planet (also termed an interstellar planet, nomad planet, free-floating planet, unbound planet, orphan planet, wandering planet, starless planet, or sunless planet) is a planetary-mass object that orbits a galactic center directly."](https://en.wikipedia.org/wiki/Rogue_planet)  
> **username_4**: I'd recommend that you consider their orbits *open, unbound or non-periodic*, but not "unstable". In orbital mechanics "unstable" usually applies only to *closed, bound, and periodic* orbits.  

---

## 1 answers

### Answer by username_1 on 2019-11-30. Score: 4 | Accepted answer

See nnnnnn's comment below.

The [NASA website](https://www.nasa.gov/feature/jpl/small-asteroid-or-comet-visits-from-beyond-the-solar-system), describing ['oumuamuam](https://en.wikipedia.org/wiki/%CA%BBOumuamua), uses the term "interstellar object." Extrasolar asteroid would seem to be another option. I haven't seen a unique word different from asteroid that originated outside of the solar system.

It seems a simple prefix is sufficient to describe objects beyond the solar system, i.e. exoplanet.

Scienfitic American has an [article](https://www.scientificamerican.com/article/two-interstellar-intruders-are-upending-astronomy/?utm_source=newsletter&utm_medium=email&utm_campaign=daily-digest&utm_content=link&utm_term=2019-11-27_featured-this-week&spMailingID=61644144&spUserID=MTE1NjM1NDM5MjAwS0&spJobID=1764375774&spReportId=MTc2NDM3NTc3NAS2) which uses the term "interstellar object."

Also, see answers to:

* [Is intrastellar commonly used by astronomers to refer to objects within our solar system?](https://astronomy.stackexchange.com/q/33680/7982)
* [Adjective for things outside our solar system](https://astronomy.stackexchange.com/q/30131/7982)

> **Comments:**
> **username_5**: Isn't *exoplanet* normally used to describe planets that orbit stars other than our Sun? As compared to *rogue planets*, which do not orbit a star.  
> **username_1**: @nnnnnn Yup, you are right.  You should write that as an answer and not just as a comment.  
> **username_5**: Well I don't think it is a complete answer because it doesn't apply to smaller objects. I guess *rogue* could also be applied to asteroids and so forth, but I didn't post an answer because I don't have sources I can quote to back that up.  

---

