Why no new plutoids/large TNOs?

BenS1985 · Jul 22, 2008

Hello all,Forgive me if I am ignorant, as this is my first post in a few years here. I had dial-up internet for many years, and have been unable to re-register for an account at Space.com until now.At any rate, my question is: It seems that for quite a few years, astronomers were discovering new Plutinos, TNOs, at a pretty decent rate. But after Pluto was relegated to the Plutino class, and Dwarf Planets became somewhat defined, the rate of discovery of these type of objects (which are interesting to me), has become non-existant.Here's the list of TNOs and associated large objects I'm refering to, and their discovery dates. Hopefully someone can fill in the void for me:<ul><li>38628 Huya (March 2000) </li><li>Varuna (November 2000)</li><li>Ixion (May 2001)</li><li>Quaoar (June 2002)</li><li>Sedna (November 2003)</li><li>90482 Orcus (February 2004)</li><li>2003 EL61 (December 2004) - Nickname 'Santa'</li><li>Eris (January 2005)</li><li>Makemake (March 2005)</li></ul>Also, looking at Harvard's list of TNO's at: http://www.cfa.harvard.edu/iau/lists/TNOs.html it would look like the discovery of such objects has decreased sharply from the rates we saw in 2002-2006..Why? Have we reached the limits of current funding for the observatories? Technology? Lack of importance? No more to discover? Just wondering, as I've always found it exciting to read about new discoveries in our solar system. I know a ton is happening with our closer planets, but I've always found TNOs exciting, as we've discovered so much recently. Any opinions, thoughts, and insights are much appreicated!

MeteorWayne · Jul 22, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Hello all,Forgive me if I am ignorant, as this is my first post in a few years here. I had dial-up internet for many years, and have been unable to re-register for an account at Space.com until now.At any rate, my question is: It seems that for quite a few years, astronomers were discovering new Plutinos, TNOs, at a pretty decent rate. But after Pluto was relegated to the Plutino class, and Dwarf Planets became somewhat defined, the rate of discovery of these type of objects (which are interesting to me), has become non-existant.Here's the list of TNOs and associated large objects I'm refering to, and their discovery dates. Hopefully someone can fill in the void for me:38628 Huya (March 2000) Varuna (November 2000)Ixion (May 2001)Quaoar (June 2002)Sedna (November 2003)90482 Orcus (February 2004)2003 EL61 (December 2004) - Nickname 'Santa'Eris (January 2005)Makemake (March 2005)Also, looking at Harvard's list of TNO's at: http://www.cfa.harvard.edu/iau/lists/TNOs.htmlit would look like the discovery of such objects has decreased sharply from the rates we saw in 2002-2006..Why? Have we reached the limits of current funding for the observatories? Technology? Lack of importance? No more to discover? Just wondering, as I've always found it exciting to read about new discoveries in our solar system. I know a ton is happening with our closer planets, but I've always found TNOs exciting, as we've discovered so much recently. Any opinions, thoughts, and insights are much appreicated! Posted by BenS1985</DIV> Interesting question. I think perhaps the largest ones near the plane of the ecliptic at less than 50 AU have been found. I'm sure the search goes on. Your list missed 1996 TO66 at ~ 900km (larger than Varuna).Searching away from the ecliptic takes longer since there's much more space to cover. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

BenS1985 · Jul 22, 2008

Ah yes, that was one I didn't put up, as I was focusing on discoveries between 2000-2006.I fully understand that the further from the ecliptic takes longer as there's more sky to cover, but I just would of thought that after the flurry of discoveries we had between 2000 and 2005, that there would of been atleast 1 or 2 discoveries that would rival any of the pre-2005 discoveries. Maybe I expect too much, no?

MeteorWayne · Jul 22, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Ah yes, that was one I didn't put up, as I was focusing on discoveries between 2000-2006.I fully understand that the further from the ecliptic takes longer as there's more sky to cover, but I just would of thought that after the flurry of discoveries we had between 2000 and 2005, that there would of been atleast 1 or 2 discoveries that would rival any of the pre-2005 discoveries. Maybe I expect too much, no? Posted by BenS1985</DIV> I just don't know, as I said, it's an interesting question.I'm sure Mike Brown and friends are still searching.If you look at your list, it was only 1 or two objects a year, so a gap of two years wouldn't be too far out of line.I'm doing some research on this...thanx for the inspiration!Wayne <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

3488 · Jul 22, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I just don't know, as I said, it's an interesting question.I'm sure Mike Brown and friends are still searching.If you look at your list, it was only 1 or two objects a year, so a gap of two years wouldn't be too far out of line.I'm doing some research on this...thanx for the inspiration!Wayne Posted by MeteorWayne</DIV>It is a fascinating question, not one I had given any thought about.More likely any more real biggies like Eris or Pluto are well above or below the ecliptic where AFAIK, the search is only just starting.I suspect that size also plays a part. For every one Eris, there may be two hundred the size of Asteroid 951 Gaspra, or one thousand the size of the Mars moon Deimos, etc.There are likely to be a great many small ones in relation to the very large ones, like Eris, Pluto, Makemake, 2003 EL61, etc.Andrew Brown.  <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

Philotas · Jul 22, 2008

In March it was posted about a new discovery, here, though I haven't heard any news on that object.   <div class="Discussion_UserSignature"> </div>

3488 · Jul 22, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>In March it was posted about a new discovery, here, though I haven't heard any news on that object.   Posted by Philotas</DIV>Some more info precovery data on 2007 UK126. Andrew Brown.   <div class="Discussion_UserSignature"> "I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before". Linda Morabito on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.http://www.launchphotography.com/ http://anthmartian.googlepages.com/thisislandearthhttp://web.me.com/meridianijournal </div>

MeteorWayne · Jul 22, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Some more info precovery data on 2007 UK126. Andrew Brown.   Posted by 3488</DIV> In perusing all the info on this object, this is what I have found.It is not listed on the Minor Planet Center (MPC) list of Trans Neptunian Objects (TNO).4 more recent discoveries have been listed. This indicated to me that the orbit is still in question.Palomar observed it a dozen times between 10/14/06 and 1/15/08. It appears to be visible from October to January.The JPL page on the objects lists the earlier observations (from 1982) with ??????. SO it appears the case is not proven that the 1982 object is the same one. It may be, but we can't yet tell for sure. At this distance (a=71 AU) the motion is very slow, even at perihelion. It's currently at 46 AU. It's only been observed for 15 months, so the orbital uncertainties are so great JPL just lists "na"Perhaps when it might be observed again this fall, the orbital uncertainties can be reduced enough to confirm whether the 1982 obs are from the same object. That would more clearly define the orbit.This would be a big TNO but not larger than Pluto. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

h2ouniverse · Jul 23, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Ah yes, that was one I didn't put up, as I was focusing on discoveries between 2000-2006.I fully understand that the further from the ecliptic takes longer as there's more sky to cover, but I just would of thought that after the flurry of discoveries we had between 2000 and 2005, that there would of been atleast 1 or 2 discoveries that would rival any of the pre-2005 discoveries. Maybe I expect too much, no? Posted by BenS1985</DIV>Hi Ben,The rate since 2000 has been about 4 large TNOs per year, and 1 very large per year on average. The diameter is very uncertain but what I call "large" are with a decent probabilty of a diameter >500km, "extra-large" with a decent probability of a diameter>1000km. As mentionned there was 2007UK126 announced this year with H=3.5 (hence a diameter probably between 400 and 1000km). But many others have been announced with absolute magnitudes lower than 5: 2006QH181 last year (H=3.8). 2007JJ43  (H=4.9) and 2007JH43(H=4.7), 2005UQ513 (H=3.7) 2005QU182 (H=3.7). 2005 RM43 (H=4.4), 2005RN43 (H=3.9), 2005RR43 5H=4.0), 2005TB190 (H=4.7), and.... Buffy the theory slayer!!! (2004XR190  H=4.5).The number of Kuiper Belt Objects (30AU<a<50AU) per year has decreased somewhat recently though in part I think because the most active discoverer (Mike Brown) has stopped the search for some time and has resumed searching this time for more distant objects (more time between the two compared pictures, to look for lower drift speed) few months ago. As he is accustomed to wait for a very long time before announcing discoveries, he may well have discovered others and be refining orbits at the time being.But the number of SDOs (a>50AU) seems to continue to increase steadily. Have a look on the same site of MPC http://www.cfa.harvard.edu/iau/lists/Centaurs.html (SDOs are listed with Centaurs!!)Also you should take care of the discovery year. TNOs spend some time before being announced. E.g. 2003EL61 has been announced in 2005. Objects 2004 VP112 and 2005 UN524 have been announced just two months ago. So there is a shift on the curve.Contrary to claims that they "have combed all the sky", they have not, by far:* they have not scanned the sky far from ecliptic (especially southern skies)* they have excluded +/- 15° on both sides of the galactic equator => 25% of the celestial vault!!!!* they had no capability to detect objects beyond 100AU (Eris was at the very limit) because they had set the parameters too low (time between two consecutive pictures) There should be logically about 50 sizeable "Sednas". Applying the principle of banality, given that we could only detect objects beneath 100AU since at best 1995 i.e. only a big decade, and that Sedna spends less than 2% of its time beneath 100AU out of a 10,800 year-long orbit, we can decently infer that there is a high probability that the current time is not special and that there are about 100% / 2% = 50 such objects in the Solar System. With the same principle of banality, you would say that at least one third of them should be larger than Sedna. Unless Sedna is in the very top of the Gaussian curve that would mean a great dose of luck.At worst we will have to wait for PAN-STARRS to be operational. Maybe Herschel when launched next year will help too.Best regards.

h2ouniverse · Jul 23, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>For every one Eris, there may be two hundred the size of Asteroid 951 Gaspra, or one thousand the size of the Mars moon Deimos, etc.There are likely to be a great many small ones in relation to the very large ones, like Eris, Pluto, Makemake, 2003 EL61, etc.Andrew Brown.  Posted by 3488</DIV> Hi Andrew, The normal distribution is even more drastic => For each 2000km-class TNOs you should have one thousand 200km-class objects, one million 20-km class objects, one billion 2-km class objects and so on... The distribution law is expected to decrease though for smaller diameters but this has still to be evidenced. This normal law distribution corresponds to allocating the same total mass per class of objects (so a factor of 10 cubed if you rank par factor of 10 on diameter, or 8=2 cubed if you rank per factor of 2). Best regards.

h2ouniverse · Jul 23, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'> itis not listed on the Minor Planet Center (MPC) list of Trans Neptunian Objects (TNO).Posted by MeteorWayne</DIV> Hi Wayne, ...and that is normal since it is an SDO (a />50 AU).=> It is listed in the Centaurs/SDOs list!!!! And this list does not show a decrease but an increase in the rate...Best regards.

Philotas · Jul 23, 2008

<div> Replying to: <DIV CLASS='Discussion_PostQuote'>Hi Andrew, The normal distribution is even more drastic => For each 2000km-class TNOs you should have one thousand 200km-class objects, one million 20-km class objects, one billion 2-km class objects and so on... The distribution law is expected to decrease though for smaller diameters but this has still to be evidenced. This normal law distribution corresponds to the same total mass per class of objects (so a factor of 10 cubed if you rank par factor of 10 on diameter, or 8=2 cubed if you rank per factor of 2). Best regards. Posted by h2ouniverse</DIV> So perhaps one day we will have a KBO designated (1 672 982 023) 2343 UK67...<img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-laughing.gif" border="0" alt="Laughing" title="Laughing" /></div> <div class="Discussion_UserSignature"> </div>

MeteorWayne · Jul 23, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Hi Wayne, ...and that is normal since it is an SDO (a />50 AU).=> It is listed in the Centaurs/SDOs list!!!! And this list does not show a decrease but an increase in the rate...Best regards. Posted by h2ouniverse</DIV> Why the SDOs would be listed with Centaurs I can't imagine. Thanx for the heads up, I'll check that list.SDOs are certainly TNOs so I'm baffled by that grouping... <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

h2ouniverse · Jul 23, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Why the SDOs would be listed with Centaurs I can't imagine. Thanx for the heads up, I'll check that list.SDOs are certainly TNOs so I'm baffled by that grouping... Posted by MeteorWayne</DIV> Hi Wayne, Me too. But they had a Centaurs list first. And it's difficult to discriminate a Centaur from some SDOs (some have perihelia beneath Neptune). Btw this list still includes 2005UN524 which really really looks like the first Uranus Trojan ( http://www.space.com/common/community/forums/?plckForumPage=ForumDiscussion&plckDiscussionId=Cat%3ac7921f8b-94ec-454a-9715-3770aac6e2caForum%3ad148ee4c-9f4c-47f9-aa95-7a42941583c6Discussion%3a53c116ab-ad33-43a5-b9e7-ec5a09c9d9f9&plckCategoryCurrentPage=0&nbsp

Best regards.

MeteorWayne · Jul 23, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Hi Wayne, Me too. But they had a Centaurs list first. And it's difficult to discriminate a Centaur from some SDOs (some have perihelia beneath Neptune). Btw this list still includes 2005UN524 which really really looks like the first Uranus Trojan ( http://www.space.com/common/community/forums/?plckForumPage=ForumDiscussion&plckDiscussionId=Cat%3ac7921f8b-94ec-454a-9715-3770aac6e2caForum%3ad148ee4c-9f4c-47f9-aa95-7a42941583c6Discussion%3a53c116ab-ad33-43a5-b9e7-ec5a09c9d9f9&plckCategoryCurrentPage=0&nbsp

Best regards. Posted by h2ouniverse</DIV> Not sure I agree with that. The "approximate" definition of a SDO (Scattered Disk Object) from Wiki (I hate to use that, but it seems to apply in this case, will drill down through the references) isThe scattered disk , with known objects at mean distances beyond 500 AU (Sedna) and aphelia beyond 1,000 AU ( (87269) 2000 OO67).Whereas the definition of Centaur is:The centaurs are a class of icy planetoids (or asteroids) named after the mythological race of centaurs. Centaurs orbit the Sun between Jupiter and Neptune, crossing the orbits of the large gas giant planets. The first centaur to be discovered was 2060 Chiron in 1977, while the largest currently known is 10199 Chariklo discovered in 1997. Personally, I don't see the overlap between objects in the solar system inside of Neptune's orbit, and bodies WELL outside the classic Kuiper Belt. (< 50 AU) <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

h2ouniverse · Jul 23, 2008

Hi Wayne NOK.Eris is an SDO. SDOs are not just with a>500AU!!!! And a to be a Centaur you have to cross the orbits of the giant planets, hance having a perihelion beneath Neptune.What do you call 2006 SQ372  (perihelion 24.1 AU  aphelion 2010 AU)? A Centaur (perihelion < Neptune) or an SDO (a >>>50 AU)?

MeteorWayne · Jul 23, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Hi Wayne NOK.Eris is an SDO. SDOs are not just with a>500AU!!!!And a to be a Centaur you have to cross the orbits of the giant planets, hance having a perihelion beneath Neptune.What do you call 2006 SQ372  (perihelion 24.1 AU  aphelion 2010 AU)? A Centaur (perihelion < Neptune) or an SDO (a >>>50 AU)? Posted by h2ouniverse</DIV> Off the top of my head I don't know. What is the inclination and semimajor axis?Categories are kind of fluid.Would 2006 UK 126 have a perihelion inside Neptune? That's not what I recall, but will have to recheck I remember it being well outside Neptune (with horribly large error bars). I certainly could be wrong...will check and report back. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

MeteorWayne · Jul 23, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Hi Wayne NOK.Eris is an SDO. SDOs are not just with a>500AU!!!!And a to be a Centaur you have to cross the orbits of the giant planets, hance having a perihelion beneath Neptune.)? Posted by h2ouniverse</DIV> Not sure what NOK means?

I understand SDOs to be objects with a > 50 AU maybe or 100AU for sure. They are not part of the classic Kuiper belt at that point, IMHO.Of course, as I said, the definitions are not well defined, and new discoveries will shift out understanding of the groupings that will naturally fall out of future data. <div class="Discussion_UserSignature"> But the Krell forgot one thing John. Monsters. Monsters from the Id. I really, really, really, really miss the "first unread post" function </div>

derekmcd · Aug 5, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>Not sure what NOK means?

I understand SDOs to be objects with a > 50 AU maybe or 100AU for sure. They are not part of the classic Kuiper belt at that point, IMHO.Of course, as I said, the definitions are not well defined, and new discoveries will shift out understanding of the groupings that will naturally fall out of future data. Posted by MeteorWayne</DIV>The debate, clearly, has not ended:http://www.space.com/scienceastronomy/080805-st-planet-debate.htmlGreat Planet Debate: Scientists Could Overturn Official Definition  Top astronomers and other planetary scientists will step into the ring this month to duke it out over a basic, yet controversial, question: What is a planet? "The Great Planet Debate: Science as Process" conference will be held from Aug. 14-16 at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md. Some astronomers see the conference as a way of cleaning up the mess created by the organization that names celestial bodies, the International Astronomical Union (IAU), which in August 2006 voted in a new definition of planet that demoted Pluto to "dwarf planet." (Under a more recent IAU decision, Pluto and similar objects are classified as "plutoids.") Many planet scientists were disgruntled over the 2006 IAU decision, which they said involved a vote of just 424 astronomers out of some 10,000 professional astronomers around the globe. The most recent decision, to categorize Pluto and such as plutoids, further ticked off many astronomers, who felt the term was developed behind closed doors. "We're going to do something that the IAU did not, which is discuss what we know about planetary bodies in the solar system and around other stars, and discuss the value of different ways of defining objects as planets and what that means," said Mark V. Sykes, director of the Planetary Science Institute in Tucson, Ariz. When the dust settles, those involved hope a consensus will stand, a classification scheme for all objects orbiting a star. "If a new consensus emerges it will easily overturn the IAU. This is not an issue," said Neil deGrasse Tyson, director of the American Museum of Natural History's Hayden Planetarium in New York. "If not, they'll stick with what they've got until something better comes along." Tyson said he doesn't see the IAU so much as a separate entity, but as part of and a reflection of the astronomical community.  Rest at link above.  <div class="Discussion_UserSignature"> <div> </div> <div>"If something's hard to do, then it's not worth doing." - Homer Simpson</div> </div>

h2ouniverse · Aug 5, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>"Many planet scientists were disgruntled over the 2006 IAU decision, which they said involved a vote of just 424 astronomers out of some 10,000 professional astronomers around the globe. ...When the dust settles, those involved hope a consensus will stand, a classification scheme for all objects orbiting a star. If a new consensus emerges it will easily overturn the IAU. " Posted by derekmcd</DIV> Hi DerekI doubt it! May be some in the US will think so but the rest of the world is much more disciplined. I went to the site and had a look at the list of speakers. 100% US. This is in no way an anti-US statement but => No decision, whatever its intelligence, will be legitimate from this assembly. Its legitimacy is even less in any case than the IAU's, that is at least an International body (even if dominated by dynamicists). If US scientists decide a definition unilaterally, it will not be accepted, even if sensible. At best this can become a motion to be proposed at next IAU's assembly.This being said, have a look at abstract ( http://gpd.jhuapl.edu/abstracts/abstractFiles/soter_Planet_Debate_Abstract.pdf&nbsp

It's so ludicrous! Both sides are far too much arrogant imo.

docm · Aug 5, 2008

I find Neil deGrasse Tyson's comment that he's "tired" of this arguement a bit disengenous given he has been evangelizing against Pluto's planet status for most of the last decade, including on several TV documentaries where he exhibited no small amount of 'attitude' on the subject. Don't start a fight you don't intend on finishing, Neil <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-tongue-out.gif" border="0" alt="Tongue out" title="Tongue out" /> <div class="Discussion_UserSignature"> </div>

derekmcd · Aug 5, 2008

Replying to: <DIV CLASS='Discussion_PostQuote'>I find Neil deGrasse Tyson's comment that he's "tired" of this arguement a bit disengenous given he has been evangelizing against Pluto's planet status for most of the last decade, including on several TV documentaries where he exhibited no small amount of 'attitude' on the subject. Don't start a fight you don't intend on finishing, Neil Posted by docm</DIV>I sure hope somebody makes up my mind for me.  I'd feel silly not being able to tell my 5 year old nephew what Pluto is."Uncle Derek?"Yes?"What's Pluto?"Umm.... Uhhh... Doh!!!  I don't know and quit asking such difficult questions!  There are thousands of our greatest minds trying to figure it out.  Now let me explain a little Quantum Electrodynamics to ya... at least we've got a grasp on that. <div class="Discussion_UserSignature"> <div> </div> <div>"If something's hard to do, then it's not worth doing." - Homer Simpson</div> </div>

Why no new plutoids/large TNOs?

BenS1985

Guest

MeteorWayne

Guest

BenS1985

Guest

MeteorWayne

Guest

3488

Guest

Philotas

Guest

3488

Guest

MeteorWayne

Guest

h2ouniverse

Guest

h2ouniverse

Guest

h2ouniverse

Guest

Philotas

Guest

MeteorWayne

Guest

h2ouniverse

Guest

MeteorWayne

Guest

h2ouniverse

Guest

MeteorWayne

Guest

MeteorWayne

Guest

derekmcd

Guest

h2ouniverse

Guest

docm

Guest

derekmcd

Guest

Similar threads

TRENDING THREADS

Latest posts

Share this page