PDA

View Full Version : Dwarf planet candidates: why the delay?



baric
2011-Feb-20, 09:46 PM
For the longest time now, we have had 5 defined dwarf planets (Pluto, Eris, Ceres, Makemake & Haumea) with tons of candidates.

However, there have been some seemingly strong candidates (Sedna, Quaoar & 2002TC302) for which no determination has been made.

Does anyone with IAU experience know why this is so? Is it insufficient observational data? Bureaucratic delays?

dtilque
2011-Feb-21, 10:47 AM
With luck, they're rethinking the advisability of having such a category in the first place. AFAICT, it has little or no scientific utility.

baric
2011-Feb-21, 01:41 PM
With luck, they're rethinking the advisability of having such a category in the first place. AFAICT, it has little or no scientific utility.

That question was settled in 2006 and was not the one I asked. But thanks!

Ara Pacis
2011-Feb-21, 09:41 PM
IIRC, there's an international legal wrangle over the naming. see Lollipop Guild, et al. v. International Astronomical Union

baric
2011-Feb-21, 10:04 PM
IIRC, there's an international legal wrangle over the naming. see Lollipop Guild, et al. v. International Astronomical Union

And this is holding up the designations on Quaoar, etc.?

dtilque
2011-Feb-23, 10:16 AM
That question was settled in 2006 and was not the one I asked. But thanks!

Yes, it would require a revote by the IAU and (from what I gather) there's little enthusiasm among the members to open that can of worms again. Plutonistas would lke to open it again, but they make up a small minority of astronomers.

Sorry I brought it up in your thread, but I just get annoyed that the category exists in the first place. Its creation was, as I understand it, part of a devious plan by the Plutonistas to sneak Pluto into planethood, but which was foiled by the other half of the plot being seen through and not passed.

Romanus
2011-Feb-23, 11:06 AM
Probably the uncertainty of mass and shape, coupled to albedo uncertainties (which seems to be the classic bugbear of KBO size estimates).

thoth II
2011-Feb-23, 12:45 PM
I think this whole definition of "dwarf planet" was a political rather than scientific definition voted by IAU under great pressure to settle the issue, and that was a good compromise. Given that "dwarf planet" is a political football, they don't want to touch that issue too often.

Jerry
2011-Feb-23, 07:39 PM
Tons of candidates?

Hasn't the dwarf planet search fallen well short of expectations?

ngc3314
2011-Feb-23, 09:43 PM
One issue must be the lack of IR detections - with only reflected sunlight, diameter measurements are hostage to what we think we know about the albedos. Get far-IR measures, you can separate albedo and size. Even Eris was faint for Spitzer; at the moment Herschel is probably the only facility even capable of doing this.

Ara Pacis
2011-Feb-24, 07:23 PM
Yes, it would require a revote by the IAU and (from what I gather) there's little enthusiasm among the members to open that can of worms again. Plutonistas would lke to open it again, but they make up a small minority of astronomers.

Sorry I brought it up in your thread, but I just get annoyed that the category exists in the first place. Its creation was, as I understand it, part of a devious plan by the Plutonistas to sneak Pluto into planethood, but which was foiled by the other half of the plot being seen through and not passed.

IIRC, the vote was undertaken by a minority of astronomers as part of a devious plan to vote when no one else was around.

baric
2011-Feb-24, 07:41 PM
IIRC, the vote was undertaken by a minority of astronomers as part of a devious plan to vote when no one else was around.

That's borderline CT. I hope you're joking! :D

If not, here's a recap:

Total members in IAU: 9785
Total registered for the 2006 conference: 2411
Total attending session when vote took place: "over a thousand"
Total who actually voted: 424

Final vote: 237-157, with 30 abstentions

So, of the 2400+ who attended the conference, it was estimated that about half of those were in the final voting session. Of those attending, less than half actually bothered to cast a vote.

Do not confuse malevolence with malaise.

Source: http://en.wikipedia.org/wiki/2006_definition_of_planet

Ara Pacis
2011-Feb-24, 11:22 PM
That's borderline CT. I hope you're joking! :D

If not, here's a recap:

Total members in IAU: 9785
Total registered for the 2006 conference: 2411
Total attending session when vote took place: "over a thousand"
Total who actually voted: 424

Final vote: 237-157, with 30 abstentions

So, of the 2400+ who attended the conference, it was estimated that about half of those were in the final voting session. Of those attending, less than half actually bothered to cast a vote.

Do not confuse malevolence with malaise.

Source: http://en.wikipedia.org/wiki/2006_definition_of_planet

I'm not, Baric, I'm mocking what dtilque wrote by using the same language he or she used here link (http://www.bautforum.com/showthread.php?p=1855218#post1855218). My point is that it was a small number of those who could have, and perhaps should, have been polled. In my political experience, 424 of >1000 is less than a quorum, making any vote null, or a straw vote in nature. Of course, I don't know exactly what the bylaws are of the IAU, so perhaps it is legitimate as far as they are concerned. But for many people, <2.5% of the electorate forcing their way on others is not legitimate based on their own experiences.

baric
2011-Feb-24, 11:59 PM
I'm not, Baric, I'm mocking what dtilque wrote by using the same language he or she used here link (http://www.bautforum.com/showthread.php?p=1855218#post1855218).

OK, phew!


My point is that it was a small number of those who could have, and perhaps should, have been polled. In my political experience, 424 of >1000 is less than a quorum, making any vote null, or a straw vote in nature. Of course, I don't know exactly what the bylaws are of the IAU, so perhaps it is legitimate as far as they are concerned.

The IAU has no quorum rules. That makes the vote legitimate.


But for many people, <2.5% of the electorate forcing their way on others is not legitimate based on their own experiences.

Hang on. None of the attendees to the IAU conference were prevented from attending or voting. The fact that most of them chose to skip the vote does not mean the decision of those who did vote represents "forcing their way".

Swift
2011-Feb-25, 02:03 PM
My point is that it was a small number of those who could have, and perhaps should, have been polled. In my political experience, 424 of >1000 is less than a quorum, making any vote null, or a straw vote in nature. Of course, I don't know exactly what the bylaws are of the IAU, so perhaps it is legitimate as far as they are concerned. But for many people, <2.5% of the electorate forcing their way on others is not legitimate based on their own experiences.
From my experience with professional societies, that is a pretty high percentage of the membership voting

baric
2011-Feb-25, 02:36 PM
From my experience with professional societies, that is a pretty high percentage of the membership voting

Also, this controversy had been brewing for a long, long time. It's not like the debate was sprung upon the members at the last minute and then rushed to a vote.

glappkaeft
2011-Feb-25, 03:19 PM
Also, this controversy had been brewing for a long, long time. It's not like the debate was sprung upon the members at the last minute and then rushed to a vote.

Plutos status has been contested since its discovery. The only reason IMO that it remained a planet for so long was the early inflated size estimates and the long delay before additional KBOs where discovered.

Ara Pacis
2011-Feb-25, 07:48 PM
The IAU has no quorum rules. That makes the vote legitimate.

As far as the IAU us concerned, sure. But this vote extends not only to themselves, but to the population as a whole. I'm sure that the election of Mubarak and others through out history was legitimatly performed according to extant rules, but that doesn't necessarily mean that the entity must be considered legitimate in the grander scheme of things. So, fine I can agree that it is binding on Astronomers, but not necessarily upon anyone else.

baric
2011-Feb-25, 09:13 PM
As far as the IAU us concerned, sure. But this vote extends not only to themselves, but to the population as a whole. I'

No it does not. It's simply an official scientific classification of Pluto made by the scientific body authorized to make such a designation.

The population as a whole is not required to refer to Pluto a "dwarf planet" any more than it is to say "please pass the sodium chloride" at the dinner table.