Dwarf Planets - How many Confirmed Dwarf Planets by 2009 IAU Congress?

[jkmccrann]

Just a question for everyone out there - how many dwarf planets do you think will be confirmed by the time the next IAU Congress convenes in 3 years time, 2009?

What are the chances that Charon will be recognised as a dwarf planet? Hmmmmmmm.

Interested to see if this poll skews in any particular direction.

[the_shaggy_one]

There are a few that are obvious, Sedna, 2005 FY9, and 2003 EL61 come to mind, plus chances are pretty good we'll find a couple more huge ones out there at Eris-type distances. Vesta might make it, since it's all nice and differentiated, and has a moderately spheroid shape.

Orcus, Varuna, 2002 UX25, 2002 TX300, Ixion, and Quaoar will probably get added in as well, but I think their diameters will fall towards the low end of the uncertainties (800-1000 km or so for most of them). All bodies larger than about 450 km are round on this side of neptune, but it remains to be seen what the threshold is in the outer reaches. I think the disks will have to be resolved, or confirmed otherwise, before these guys get into the club.

Charon will probably stay a sattelite. There's not as much of a need for it to be defined as a dwarf planet. There's a lot of 'that would be neat'-factor to the idea of Charon as a dwarf planet, and not much else, despite the uniqueness of it's orbit.

[Saluki]

I think it is a little premature to guess at this. IMO, the definition itself is still on shaky ground, and it would not suprise me at all to see it as a major topic of the next meeting.

[CuddlySkyGazer]

My guess isn't one of the options on your poll. I suspect that there will zero or one additional dwarf planets recognised by the 2009 Congress. I don't think there will be sufficient information by then. By what means will we find out more about objects we already know of that we don't already know? And objects of the required size are not very frequent discoveries - so very unlikely that we'll discover more than another one by then.

[Kullat Nunu]

I voted accidentally 13+ (I was somehow thinking planets + dwarf planets). 6-8 official dwarf planets sound realistic although there certainly are 13+ potential dwarf planets, not to mention that there's still 3 years to find new giant TNOs. If they're really lazy designating new dwarf planets, there will be only 5 of them in 2009. I can't see why 2003 EL61 and 2005 FY9 wouldn't get a dwarf planet status by 2009 (2003 EL61 isn't round, but it is in a hydrostatic equilibrium).

[antoniseb]

I voted 13+, but another possibility is that they will not explicitly 'recognize' any.

[Kullat Nunu]

The IAU Circular #8747 (http://cfa-www.harvard.edu/iau/special/08747.pdf) which announced the names of Eris and Dysnomia and assigned Pluto with a minor planet number, mentions "two other new potential dwarf-planet candidates". They're 2003 EL61 and 2005 FY9) although the circular doesn't mention them explicitly.

Eris' name was accepted at a record speed (in a mere week), but it doesn't seem to be the case with the two other objects. However, since their status is relatively certain and they're already numbered, it's only a matter of time when they get their permanent names.

[baric]

We have 3 now, 2 in queue, and at least 5 waiting to be re-evaluated. That's at least 10 known dwarf planets already -- with more certainly waiting to be discovered.

If there's still dissension in the ranks about the new criteria, the IAU will probably accelerate the evaluation process to make it obvious to the general public that we would already have 20+ "planets" if we did not make an orbital distinction.

Without public support, the "Keep Pluto as a planet" campaign will lose 99% of its momentum.

[CuddlySkyGazer]

The reason only three dwarf planets were named in August was that there was insufficient information about the other objects listed as possibles to decide whether they were dwarf planets or not. If the IAU had the information, they would already have made the decision.

By what means is any further information (relevant information) going to be found about these objects before 2009? Any space probes going there? Any big new telescopes coming on line whose operators will consider this question a high priority?

Absent a new discovery, I don't think there'll be a new dwarf planet recognised until the NASA mission Dawn gets to Vesta (currently slated for October 2011), and perhaps not even then (as Vesta might not satisfy the criteria).

[Kaptain K]

What are the chances that Charon will be recognised as a dwarf planet?
Zero! Charon is a moon.

[Kullat Nunu]

From the dwarf planet Q & A (http://www.iau2006.org/mirror/www.iau.org/iau0603/iau0603_Q_A2.html):


Q: Is Pluto’s moon Charon a dwarf planet?

A: For now, Charon is considered just to be Pluto’s moon. The idea that Charon might qualify to be called a dwarf planet on its own, may be considered later. (Charon may receive consideration because Pluto and Charon are comparable in size and orbit each other, rather than just being a moon orbiting a planet.)