<p>Source: <a href="https://exoplanets.nasa.gov/5-ways-to-find-a-planet/" rel="nofollow noreferrer">https://exoplanets.nasa.gov/5-ways-to-find-a-planet/</a></p>

<p>Currently, we have five known ways of detecting exoplanets. Your question asked about observing planets that are escaping stellar systems. These are detecting shifts in stellar velocity, detecting shifts in stellar position, searching for transits, direct imaging, and detecting the gravitational lensing of light.</p>

<p>A planet that's being ejected from the orbit of a star would have increasingly small gravitational effects on its parent star as it flies further away through space. It would also no longer have a regular orbit and transits and would be poorly lit in the interstellar medium, making our detection efforts largely in vain. So I would suggest that the data we could glean from a planet going rogue is about the same data we can glean from any regular exoplanet.</p>

CC BY-SA 4.0
2019-05-23T10:32:43.853Z
"A planet that's being ejected from the orbit of a star would have increasingly small gravitational effects on its parent star as it flies further away through space. " Which is of course a very unlikely event. In orbital mechanics, you're bound or you're unbound. Interaction with a third body can destabilize orbits, but that doesn't necessarily change an ellipse into a hyperbola.
AtmosphericPrisonEscape
CC BY-SA 4.0
2019-05-23T19:36:51.803Z
uhoh: I assumed the question asked about a planet near the star on an escape trajectory.
AtmosphericPrisonEscape: Planets are detected and observed by their gravitational effects on their parent star. (Doppler-shift detection works this way.) Thus, as a planet flies farther, it would have less gravitational pull on its parent star and less opportunity to be detected.
Cloudy7
CC BY-SA 4.0
2019-05-23T07:18:37.370Z
The last sentence is unjustified. "*So I would suggest that the data we could glean from a planet going rogue is about the same data we can glean from any regular exoplanet.*" If a planet is light years away from any star, then probably there would be **no opportunities for research** whatsoever because it would not be in any way detectable. Unless of course it got close enough to our solar system that it could cause some measurable gravitational perturbations or start interacting with light from our Sun.
uhoh
CC BY-SA 4.0
2019-05-22T23:59:45.677Z
2019-05-22T23:59:45.677Z
Cloudy7
<p>I was perusing the exoplanet database and looking for some of the more extreme orbits, when I happened upon <strong>HD 20782 B</strong>:</p>

<p><a href="http://exoplanets.org/detail/HD_20782_b" rel="nofollow noreferrer">http://exoplanets.org/detail/HD_20782_b</a></p>

<p>Which is also listed (in two sentences) <a href="https://en.wikipedia.org/wiki/HD_20782_b" rel="nofollow noreferrer">on wikipedia</a>, so there's not a whole lot of information. However, the first thing I noticed was that it was almost at escape velocity!</p>

<p><a href="https://i.sstatic.net/tjV9u.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/tjV9u.png" alt="enter image description here"></a></p>

<p>I guess not much is known, but my overall question is:</p>

<p><strong>Would an exoplanet on an escape trajectory offer us any opportunities for research that have yet to be performed? What would those opportunities be? The answer can be a justified no (E.G. once the planet leaves the host star, we can't observe the doppler shift anymore).</strong></p>

<hr>

<p>Imaginary Bonus Points: have there ever been any observed as escaping/becoming rogue planets?</p>

<exoplanet><escape-velocity>
Are exoplanets which are above escape velocity of particular interest?
Magic Octopus Urn
# Are exoplanets which are above escape velocity of particular interest?

(Asked by: username_0 on 2019-05-22)

I was perusing the exoplanet database and looking for some of the more extreme orbits, when I happened upon **HD 20782 B**:

<http://exoplanets.org/detail/HD_20782_b>

Which is also listed (in two sentences) [on wikipedia](https://en.wikipedia.org/wiki/HD_20782_b), so there's not a whole lot of information. However, the first thing I noticed was that it was almost at escape velocity!

[![enter image description here](https://i.sstatic.net/tjV9u.png)](https://i.sstatic.net/tjV9u.png)

I guess not much is known, but my overall question is:

**Would an exoplanet on an escape trajectory offer us any opportunities for research that have yet to be performed? What would those opportunities be? The answer can be a justified no (E.G. once the planet leaves the host star, we can't observe the doppler shift anymore).**

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Imaginary Bonus Points: have there ever been any observed as escaping/becoming rogue planets?

**Tags:** exoplanet, escape-velocity


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## 1 answers

### Answer by username_1 on 2019-05-22. Score: 0

Source: <https://exoplanets.nasa.gov/5-ways-to-find-a-planet/>

Currently, we have five known ways of detecting exoplanets. Your question asked about observing planets that are escaping stellar systems. These are detecting shifts in stellar velocity, detecting shifts in stellar position, searching for transits, direct imaging, and detecting the gravitational lensing of light.

A planet that's being ejected from the orbit of a star would have increasingly small gravitational effects on its parent star as it flies further away through space. It would also no longer have a regular orbit and transits and would be poorly lit in the interstellar medium, making our detection efforts largely in vain. So I would suggest that the data we could glean from a planet going rogue is about the same data we can glean from any regular exoplanet.

> **Comments:**
> **username_3**: The last sentence is unjustified. "*So I would suggest that the data we could glean from a planet going rogue is about the same data we can glean from any regular exoplanet.*" If a planet is light years away from any star, then probably there would be **no opportunities for research** whatsoever because it would not be in any way detectable. Unless of course it got close enough to our solar system that it could cause some measurable gravitational perturbations or start interacting with light from our Sun.  
> **username_2**: "A planet that's being ejected from the orbit of a star would have increasingly small gravitational effects on its parent star as it flies further away through space. " Which is of course a very unlikely event. In orbital mechanics, you're bound or you're unbound. Interaction with a third body can destabilize orbits, but that doesn't necessarily change an ellipse into a hyperbola.  
> **username_1**: username_3: I assumed the question asked about a planet near the star on an escape trajectory. username_2: Planets are detected and observed by their gravitational effects on their parent star. (Doppler-shift detection works this way.) Thus, as a planet flies farther, it would have less gravitational pull on its parent star and less opportunity to be detected.  

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