<p>In the linked article by A. Bouchard and <a href="https://www.smithsonianmag.com/smart-news/new-definition-would-make-moon-and-pluto-planets-180962379/" rel="nofollow noreferrer">another by J. Daley</a>,
the words &quot;in the journal <em>Lunar and Planetary Science</em>&quot; link not to a journal article
but to a poster in a <a href="https://www.hou.usra.edu/meetings/lpsc2017/pdf/sess323.pdf" rel="nofollow noreferrer">K-12 education session</a>
at the <a href="https://www.hou.usra.edu/meetings/lpsc2017/" rel="nofollow noreferrer">2017 Lunar and Planetary Science Conference</a>.</p>
<p>First author Kirby Runyon <a href="https://www.universetoday.com/133525/sad-pluto-110-planets-solar-system-instead/" rel="nofollow noreferrer">told Universe Today in 2017</a> that he would not submit this geophysical definition to <a href="https://www.iau.org/administration/statutes_rules/working_rules/#WorkRulIV" rel="nofollow noreferrer">the IAU process</a>:</p>
<blockquote>
<p>We in the planetary science field don’t need the IAU definition...
If [the geophysical definition] is the definition that people use and what teachers teach, it will become the de facto definition, regardless of how the IAU votes in Prague.</p>
</blockquote>
<p>It was <a href="https://www.iau.org/news/announcements/detail/ann18029/" rel="nofollow noreferrer">not presented</a> at the 2018 IAU General Assembly in Vienna.
I don't know where Bouchard got &quot;has been submitted to the IAU for review.&quot;</p>

CC BY-SA 4.0
2021-01-03T23:33:28.500Z
2021-01-03T23:33:28.500Z
Mike G
<p>In 2017, Alan Stern et al. <a href="https://www.labroots.com/trending/space/5455/redefining-planet-is-pluto-planet-again" rel="nofollow noreferrer">submitted a geophysical planet definition to the IAU</a> for review which states</p>
<p>“A planet is a sub-stellar mass body that has never undergone nuclear fusion and that has sufficient self-gravitation to assume a spheroidal shape adequately described by a triaxial ellipsoid regardless of its orbital parameters.”</p>
<p>Obviously, the IAU didn't accept it (as yet) but does anyone know what exactly the IAU stated about the draft and whether it is still being debated or entirely discarded etc.?</p>
<p>I'm just asking if it is possible to know the IAU's reaction. While users may have opinions on how reasonable the proposal is or isn't, <em>please don't post opinions as answers.</em></p>

CC BY-SA 4.0
2021-01-03T19:59:51.803Z
What's the point of the question?
James K
CC BY-SA 4.0
2021-01-03T21:56:46.083Z
They most likely were bored as there is little need and it just serves the purpose to get Pluto back to planethood. Evil tongues say that it's an endeavour to try and get back at least one planet discovered over in the new world.
planetmaker
CC BY-SA 4.0
2021-01-03T22:01:25.643Z
@JamesK to provide a mechanism by which an answer to "What was IAU's reaction to Alan Stern's 2017 proposal?" can be posted. Questions don't generally have "points", questions enable answers.
uhoh
CC BY-SA 4.0
2021-01-04T07:03:38.633Z
@planetmaker Evil tongues claim it would just serve the purpose to get Pluto back to planethood.
Greenhorn
CC BY-SA 4.0
2021-01-04T09:19:27.977Z
@Greenhorn yes... but what's the point? Pluto simply is not special. And there's no purpose served if we end up with dozens of planets. Dwarf planets is a useful category.
planetmaker
CC BY-SA 4.0
2021-01-04T10:37:13.713Z
@planetmaker New Horizons proved that Pluto is a very special body. Triton and Eris are similar, but I'd say they're all (respectively these types of bodies) very interesting bodies. What does 'purpose' have to do with what a planet is or not? For a long time it was clear what a planet is: a spherical body usually orbiting a star that is neither a star nor a moon. It's not like you'd be forced to learn all names of planets (just like you aren't forced to learn those of moons). Just the eight largest ones and, for historical reasons, Ceres and Pluto probably (and the hypothetical planet Nine).
Greenhorn
CC BY-SA 4.0
2021-01-04T10:37:58.637Z
@planetmaker The geophysical definition considers all spherical moons 'planets' and I _don't_ agree with it, just to make it clear.
Greenhorn
CC BY-SA 4.0
2021-01-04T12:27:41.750Z
Bouchard wrote nonsense with *Charon is one of them and is nearly the same size as Pluto to begin with. Its size imposes a strong gravitational influence on Pluto that prevents it from meeting the final criteria of clearing its orbital neighborhood.* One of the ways a planet can clear its orbital neighborhood is by capturing (or have been formed with) lesser objects as moons.
David Hammen
CC BY-SA 4.0
2021-01-04T12:57:21.603Z
@DavidHammen You're right, that statement got my attention too.
Greenhorn
<history><terminology><definition><iau>
What happened to the 2017 proposal on redefining planethood? Is this information available?
Greenhorn
# What happened to the 2017 proposal on redefining planethood? Is this information available?

(Asked by: username_0 on 2021-01-03)

In 2017, Alan Stern et al. [submitted a geophysical planet definition to the IAU](https://www.labroots.com/trending/space/5455/redefining-planet-is-pluto-planet-again) for review which states

“A planet is a sub-stellar mass body that has never undergone nuclear fusion and that has sufficient self-gravitation to assume a spheroidal shape adequately described by a triaxial ellipsoid regardless of its orbital parameters.”

Obviously, the IAU didn't accept it (as yet) but does anyone know what exactly the IAU stated about the draft and whether it is still being debated or entirely discarded etc.?

I'm just asking if it is possible to know the IAU's reaction. While users may have opinions on how reasonable the proposal is or isn't, *please don't post opinions as answers.*

**Tags:** history, terminology, definition, iau

> **Comments:**
> **username_1**: What's the point of the question?  
> **username_2**: They most likely were bored as there is little need and it just serves the purpose to get Pluto back to planethood. Evil tongues say that it's an endeavour to try and get back at least one planet discovered over in the new world.  
> **username_3**: @JamesK to provide a mechanism by which an answer to "What was IAU's reaction to Alan Stern's 2017 proposal?" can be posted. Questions don't generally have "points", questions enable answers.  
> **username_0**: @username_2 Evil tongues claim it would just serve the purpose to get Pluto back to planethood.  
> **username_2**: @username_0 yes... but what's the point? Pluto simply is not special. And there's no purpose served if we end up with dozens of planets. Dwarf planets is a useful category.  
> **username_0**: @username_2 New Horizons proved that Pluto is a very special body. Triton and Eris are similar, but I'd say they're all (respectively these types of bodies) very interesting bodies. What does 'purpose' have to do with what a planet is or not? For a long time it was clear what a planet is: a spherical body usually orbiting a star that is neither a star nor a moon. It's not like you'd be forced to learn all names of planets (just like you aren't forced to learn those of moons). Just the eight largest ones and, for historical reasons, Ceres and Pluto probably (and the hypothetical planet Nine).  
> **username_0**: @username_2 The geophysical definition considers all spherical moons 'planets' and I _don't_ agree with it, just to make it clear.  
> **username_4**: Bouchard wrote nonsense with *Charon is one of them and is nearly the same size as Pluto to begin with. Its size imposes a strong gravitational influence on Pluto that prevents it from meeting the final criteria of clearing its orbital neighborhood.* One of the ways a planet can clear its orbital neighborhood is by capturing (or have been formed with) lesser objects as moons.  
> **username_0**: @DavidHammen You're right, that statement got my attention too.  

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## 1 answers

### Answer by username_5 on 2021-01-03. Score: 2 | Accepted answer

In the linked article by A. Bouchard and [another by J. Daley](https://www.smithsonianmag.com/smart-news/new-definition-would-make-moon-and-pluto-planets-180962379/),
the words "in the journal *Lunar and Planetary Science*" link not to a journal article
but to a poster in a [K-12 education session](https://www.hou.usra.edu/meetings/lpsc2017/pdf/sess323.pdf)
at the [2017 Lunar and Planetary Science Conference](https://www.hou.usra.edu/meetings/lpsc2017/).

First author Kirby Runyon [told Universe Today in 2017](https://www.universetoday.com/133525/sad-pluto-110-planets-solar-system-instead/) that he would not submit this geophysical definition to [the IAU process](https://www.iau.org/administration/statutes_rules/working_rules/#WorkRulIV):

> We in the planetary science field don’t need the IAU definition...
> If [the geophysical definition] is the definition that people use and what teachers teach, it will become the de facto definition, regardless of how the IAU votes in Prague.

It was [not presented](https://www.iau.org/news/announcements/detail/ann18029/) at the 2018 IAU General Assembly in Vienna.
I don't know where Bouchard got "has been submitted to the IAU for review."


---

