Finally, it's Plutoid

[h2ouniverse]

<p>The IAU has come with a name for Pluto-like objects.</p><p>Not Pluton. Not Planetoid. But Plutoid.</p><p>Stern is still con-Stern-ated.</p><p>http://www.space.com/scienceastronomy/080611-plutoid-planets.html</p><p>http://space.newscientist.com/article/dn14118-plutolike-objects-to-be-called-plutoids.html?DCMP=ILC-hmts&nsref=space2_head_Pluto-like%20objects%20to%20be%20called%20'plutoids'</p><p>&nbsp;Apparently, not all transneptunian dwarf planets would qualify. They need to be with a high albedo. Probably Eris, EL61... But not the darkest ones.</p><p>&nbsp;</p>

 

[MeteorWayne]

Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The IAU has come with a name for Pluto-like objects.Not Pluton. Not Planetoid. But Plutoid.Stern is still con-Stern-ated.http://www.space.com/scienceastronomy/080611-plutoid-planets.htmlhttp://space.newscientist.com/article/dn14118-plutolike-objects-to-be-called-plutoids.html?DCMP=ILC-hmts&nsref=space2_head_Pluto-like%20objects%20to%20be%20called%20'plutoids'&nbsp;Apparently, not all transneptunian dwarf planets would qualify. They need to be with a high albedo. Probably Eris, EL61... But not the darkest ones.&nbsp; <br />Posted by h2ouniverse</DIV><br /><br />Based on the description, Plutino has always seems like the best name for plutinos.... <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[jmilsom]

<p>Just saw this. Here is an AP science article on yahoo: </p><p>&nbsp;http://news.yahoo.com/s/ap/20080611/ap_on_sc/sci_plutoid</p><p>Alan Stern&nbsp;is quoted as saying:</p><p><em>It was not enough to satisfy leading Pluto-as-a-planet advocate Alan Stern, a former NASA space sciences chief and principal investigator on a mission to Pluto. Stern said a rival group could be formed to the IAU, which he said was too secretive in its decision-making.</em></p><p><em>"It's just some people in a smoke-filled room who dreamed it up," Stern said. "Plutoids or hemorrhoids, whatever they call it. This is irrelevant."</em><br /><br />I agree with Alan Stern. There should be a rival to the IAU, that is open and democratic. It seems ludicrous to me in this day and age, where the science of space missions is shared to all and sundry immediately, that an elitist group that excludes some of the greatest minds in the astronomy field can make these decisions behind closed doors. </p><p>Not to repeat arguments on previous threads, but the ice dwarfs should be a 'class' of planets in a new taxonomy of celestial bodies. The new IAU definitions lack foresight. </p> <div class="Discussion_UserSignature"> </div>

 

[michaelmozina]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Based on the description, Plutino has always seems like the best name for plutinos.... <br /> Posted by MeteorWayne</DIV></p><p>Or maybe 'planetinos' or planetoids?&nbsp; &nbsp; I guess no matter what they picked, someone would have complained. &nbsp;</p> <div class="Discussion_UserSignature"> It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. - Kristian Birkeland </div>

 

[h2ouniverse]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Based on the description, Plutino has always seems like the best name for plutinos.... <br />Posted by MeteorWayne</DIV><br /><br />Hi Wayne.</p><p>&nbsp;</p><p>Take care. Plutino has already a meaning (for dynamicists): means any body of any size (dwarf planet or pebble) that is caught in a 3:2 mean motion resonance with Neptune, as Pluto, Orcus, Ixion and hundreds of smaller discovered objects are.</p><p>Eris is not resonant, and at about 27:8 of Neptune's period. (9:4 with respect to the plutinos).</p><p>Best regards.</p>

 

[MeteorWayne]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Hi Wayne.&nbsp;Take care. Plutino has already a meaning (for dynamicists): means any body of any size (dwarf planet or pebble) that is caught in a 3:2 mean motion resonance with Neptune, as Pluto, Orcus, Ixion and hundreds of smaller discovered objects are.Eris is not resonant, and at about 27:8 of Neptune's period. (9:4 with respect to the plutinos).Best regards. <br />Posted by h2ouniverse</DIV></p><p>I agree 100%. Pluto is a Plutino; i.e TNOs in&nbsp;3:2 resonant orbit with Neptune. It surely is&nbsp;the largest of the Plutino&nbsp;subset of the TNOs. Plutoid implies a common life for all the larger TNOs which is not necessarily correct.</p><p>The other stuff in the scattered disk, and Kuiper Belt are differing subsets.</p><p>The point is that this is the largest trans Neptunian object we knew about 10 years ago.</p><p>I'd rather stick with dwarf planet and plutino that create this Plutoid category. If applied to the other large objects in the outer solar system, it is not appropriate, IMHO.</p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[h2ouniverse]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Just saw this. Here is an AP science article on yahoo: &nbsp;http://news.yahoo.com/s/ap/20080611/ap_on_sc/sci_plutoidAlan Stern&nbsp;is quoted as saying:It was not enough to satisfy leading Pluto-as-a-planet advocate Alan Stern, a former NASA space sciences chief and principal investigator on a mission to Pluto. Stern said a rival group could be formed to the IAU, which he said was too secretive in its decision-making."It's just some people in a smoke-filled room who dreamed it up," Stern said. "Plutoids or hemorrhoids, whatever they call it. This is irrelevant."I agree with Alan Stern. There should be a rival to the IAU, that is open and democratic. It seems ludicrous to me in this day and age, where the science of space missions is shared to all and sundry immediately, that an elitist group that excludes some of the greatest minds in the astronomy field can make these decisions behind closed doors. Not to repeat arguments on previous threads, but the ice dwarfs should be a 'class' of planets in a new taxonomy of celestial bodies. The new IAU definitions lack foresight. <br />Posted by jmilsom</DIV><br /><br />Hi jmilsom,</p><p>&nbsp;I am quite skeptic too about "absolute" taxonomy in general and agree with you that IAU has lacked foresight in its definition. For taxonomy, just think of the asteroids taxonomy, based on spectral properties, that proves quite inappropriate as many objects are difficult to categorize. Moreover, it does not tend to really represent physical properties (best correlated with the albedo). I would prefer that each discipline has its taxonomy, without trying to force other disciplines to bend to their arrangement (this would mean to assume de facto correlations between different physical properties, where such correlation may simply not exist at all...). If dynamicists want to mark a difference, thay can distinguish "dominant planets" from "minor planets" (and should also distinguish by the same token "dominant moons" from "minor moons"). If astrogeologists want to distinguish a "planetary object" from an asteroid, or a "plutoid" or "Pluto-like" from another kind of body all the best too.</p><p>Regarding IAU though, I disagree with you. I am afraid this "upheaval" of some US planetologists might backlash, as this would appear again as a plot against an organization that is not US-controlled. This is in no way an anti-US statement from my behalf, but the situation is such currently that this would imo be counterproductive for US scientists' credibility. To protect Pluto because it was the only "planet" discovered by an American is quite ludicrous: almost all dwarf planet candidates have been discovered by US astronomers or by US-led teams, and that should be enough by far to reassure&nbsp;American nationalists who might fear the leadership in science is not recognized at its deserved value. There is total indifference to Pluto's status for man-in-the-street btw anywhere else in the world, which means that the only thing non-US guys&nbsp;will remember will be a nationalistic issue. When&nbsp;it comes to defining names or categories to be used by Mankind, you cannot organize "democratic" contests. Think of the cheesy Eurovision song contest. Or the laughable "new seven wonders" contest with so-called "democratic" internet voting, and you will get a glimpse of the ridicule and embarassment whenever you let a random crowd decide what a cat is,&nbsp;let alone astronomical taxonomy, even more when nationalistic considerations begin to count. Note that this stands too for the complete community of astronomers/planetologists/...(for what "complete community" means) &nbsp;that is not balanced at all in its composition in terms of international representativity, and would therefore be biased too in some way or another either nation vs nation or discipline vs discipline. Yes, a collegial organization is elitist with the drawbacks that come with, but you cannot leave&nbsp;normative work&nbsp;to an undefined plethoric assembly. Would be like accepting "google spelling" as the supreme authority defining what English language should be. Or let the philosophical opinion of the majority&nbsp;determine which scientific theory should be&nbsp;taught in school and which one should not. Science is about a successful modelling of the world and as such has some absolutes, that do not depend on popular will. It's normal that Academia determines its decisions, in any field, in a structured collegial way with committees rather than mimic democratic processes with one man-one vote. </p><p>Best regards.</p>

 

[Philotas]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The IAU has come with a name for Pluto-like objects.Not Pluton. Not Planetoid. But Plutoid.Stern is still con-Stern-ated.http://www.space.com/scienceastronomy/080611-plutoid-planets.htmlhttp://space.newscientist.com/article/dn14118-plutolike-objects-to-be-called-plutoids.html?DCMP=ILC-hmts&nsref=space2_head_Pluto-like%20objects%20to%20be%20called%20'plutoids'&nbsp;Apparently, not all transneptunian dwarf planets would qualify. They need to be with a high albedo. Probably Eris, EL61... But not the darkest ones.&nbsp; <br />Posted by h2ouniverse</DIV><br /><br />Well it does make some sense; more practical than 'spherical KBO'. But that raises another concern of accuracy, what about spherical Oort cloud objects? That far out, do they have most of their atmosphere frozen out permanently?</p><p>&nbsp;As for the term 'dwarf planet', it doesn't make sense. Earth is much of a dwarf planet if Jupiter is a planet; considering that Jupiter has more mass than all of the other planets combined.&nbsp;It does indeed make much more sense to call Ceres a planet than Jupiter, considering that it is much more similar to Earth in terms of composition.</p> <div class="Discussion_UserSignature"> </div>

 

[jmilsom]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Hi jmilsom,&nbsp;I am quite skeptic too about "absolute" taxonomy&nbsp;......etc <br />Posted by h2ouniverse</DIV></p><font size="2">Hi H20universe, </font><font size="2"><p>I appreciate your comments. Very good points. However, I still wonder if this particular collegial organisation limits the academic input and debate that could be brought to bear on the subject. </p><p>I understand the structure of the IAU and the how the vote took place, but what worries me is how the defintion was drafted in the first place. Who was on that committee? As I understand it a select committee drafted it then presented it to the participants without reasonable time for debate, critique and discourse. How many on the committe were those involved with the exploding number of planetary bodies? i.e. those working on the outer solar system and exo-planets? Given the importance and long standing impact of a change in planetary nomenclature, couldn't they be a little more transparent as to who is selected for drafting and why? And why not take a few years and specifically invite academic papers on the subject? So those who are really leading the field can have a fair opportunity for input?</p><p>I agree with many of your comments above, but can't help feeling the IAU is a little dated in its structure and how it approaches these decisions.</p><p><br /><br />&nbsp;</p></font> <div class="Discussion_UserSignature"> </div>

 

[h2ouniverse]

<p>CORRECTION: Unlike what was written in my first post and Mike Brown's initial understanding, the albedo will not be a factor in deciding whether a body is a plutoid or not.</p><p>&nbsp;The stuff with H<1 has been clarified. (see IAU site http://www.iau.org/public_press/news/release/iau0804/)</p><p>So:</p><p>* any dwarf planet with a semi-major axis larger than that of Neptune will end up as "plutoid" one day or another</p><p>* if absolute magnitude H is lower than 1, the probability that it is a dwarf planet is very high (hydrostatic equilibrium), so the body will be considered as "dwarf planet" and "plutoid" by default;&nbsp;the naming process will involve the committee in charge of naming planets and planetary features PLUS the committee in charge of naming small bodies, so as to guarantee that the name proposed by the discoverer is culturally acceptable AND not already used for a minor body; </p><p>* for H>1, the naming will be decided by the regular committee for small bodies (based on discoverer's proposal); the body will be classified as "dwarf planet" and "plutoid" only once evidence is brought that it is hydrostatic equilibrium</p><p>* if after investigation, a H<1 body is proved to be&nbsp;not hydrostatically relaxed, it will be declassified from plutoid/dwarf planet to SSSB (Solar System Small Body), but will keep its name.</p><p>So finally these are good news for all of us who deplore that the large transneptunians are not named yet. <strong>2005FY9 and 2003EL61 (both at H<1) should be named soon as "dwarf planets" and "plutoids".</strong> Same for all other bodies, who can now be named more easily, this time with the regular committee. These latter are all at H>3. (the ones between 1 and&nbsp;3 are Sedna, Orcus&nbsp;and Quaoar, and are already named).<br />Also, that should please the tenents of the planetary status of dwarf planets, since this means that they now receive the same care as the features of full-fledged planets when receiving a name, when their minimum guaranteed diameter is large enough (H<1 guarantees a diameter /> 830km).</p><p>sorry for this initial confusion (but I was in good company)</p><p>Best regards.</p>