17 August 2006

At least they haven't proposed changing the actual name of anything, just what category it falls into. The International Astronomical Union unveiled its proposed definition of a planet, and everything else out there, in Prague yesterday. Here is how at all shakes out, at least as of today.

Planets
Classical Planet	Dwarf Planet	Pluton	Small Solar System Body
Mercury
Venus
Earth
Mars
	(1) Ceres
Jupiter
SATURN
Uranus
Neptune
		Pluto
		Charon
		2003 UB313 (Xena)
			some of the minor planets (asteroids)

Other Potential Planets
Asteroids	Trans-Neptunian Objects
Vesta Pallas Hygiea	2003 EL61 2005 FY9 Sedna Orcus Quaoar Varuna 2002 TX300 Ixion 2002 AW197

When you step back and look at it nothing really happened to what we grew up with as planets. Pluto is still a planet, it just isn't in the same league with the other eight. Ceres, which was thought to be a planet when it was discovered in the 1800s, is going to be a planet again and the only one in its particular class. And Pluto will have company in its class with the initial addition of three new planets and probably more later on.

All the textbooks and field guides will have to be replaced as well as the orrerys and teachers are going to have to find a replacement for my very easygoing mother just served us nine pies. This could be the jolt the economy needs.

IAU graphic

A Wired article says that there will be two brainstorming sessions before the formal vote on the proposal on next Thursday, 24Aug06. That could, I am assuming, change the proposal before it is ultimately voted upon. Depending on which news article you read and whether they are quoting Binsel from MIT who was on the committee that wrote the definition, or quote someone from one of the other camps, the proposal has a good chance of passing, will be roundly defeated, or the vote will be split three ways which would also defeat the proposal. The Wired article also says that the committee that had to bring the proposal to the membership after it was submitted to them by the committee that wrote it apparently doesn't propose anything to the membership that they don't think will get the necessary 2/3 majority needed for passage (so why even put it up for a vote). In any case, we will have to wait until after the membership vote at the end of next week to see what changes, if any, are made.

Along the lines of voting, a little piece that has been lost among the hoopla over is it or is it not, at its last meeting the IAU voted to amend its rules so that member scientists couldn't vote on things like this. So they had to do some procedural housekeeping to give the membership back the right to vote since everyone wants to have a say in the fate of Pluto. I haven't heard anything said about rescinding the rescintion after the Pluto vote.

The IAU proposal:

The IAU therefore resolves that planets and other Solar System bodies be defined in the following way:

(1) A planet is a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet.

(2) We distinguish between the eight classical planets discovered before 1900, which move in nearly circular orbits close to the ecliptic plane, and other planetary objects in orbit around the Sun. All of these other objects are smaller than Mercury. We recognize that Ceres is a planet by the above scientific definition. For historical reasons, one may choose to distinguish Ceres from the classical planets by referring to it as a "dwarf planet."

(3) We recognize Pluto to be a planet by the above scientific definition, as are one or more recently discovered large Trans-Neptunian Objects. In contrast to the classical planets, these objects typically have highly inclined orbits with large eccentricities and orbital periods in excess of 200 years. We designate this category of planetary objects, of which Pluto is the prototype, as a new class that we call "plutons".

(4) All non-planet objects orbiting the Sun shall be referred to collectively as "Small Solar System Bodies".

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Observing Location	Bryant Park
Observational Period	1215-1230 EDT
Atmospheric Conditions	It is another great day out. It is warm but not too hot yet and there is a moderate breeze. When I left The Bronx and got at the high point on the elevated subway, over the Bronx River, I could see long lines of building cumulus clouds on the horizon that looked like they are out at sea. From Manhattan I could see clouds low over the ends of all of the streets and avenues but none overhead. No boiling. It is nice sitting here looking to the south at the sun then turning a bit to the west and seeing the old crescent Moon clearly visible half way up in the sky. Transparency Good Seeing Excellent
Instruments	Canon 15x50 IS binocular w/Baader AstroSolar filter film - Charlie
Observing Party	Charlie Ridgway

Target Sunspots Constellation Leo Category Solar Time 20060817.1215 EDT Comments 904 The penumbra around the p-spot has grown and the umbra doesn't look as round as it did yesterday. The spots of the f-spot are more stretched out and the penumbra is barely visible. There appears to be a small spot close to the trailing edge of the p-spot. It looks like the spot has undergone shear but it is oriented horizontally across the disk so shouldn't be exhibiting the effects of differential rotation.   Groups Spots R North 0 0 0 South 1 4 14 Total 1 4 14 R = (Geoups * 10) + Spots) There is a news story on Universe Today about a tiny sunspot that was observed for three hours on 31Jul06 that could be the harbinger of the next sunspot cycle. The article says the spot was so insignificant that it wasn't given a number. I went back in the blog and found that at 1815 EDT on 30Jul06 I observed a tiny sunspot that I didn't subsequently identify. That would make the sunspot observed at 2315 30Jul06 UTC and their article says it persisted for three hours and their associated image is for 0000 UTC on that date. So I think I observed this spot.

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Observing Location	MetOval
Observational Period	2100-2300 EDT
Atmospheric Conditions	When I got home I could see some cirrostratus clouds lit up orange in the setting sun so I thought it was a little risky heading downtown to observe. By 2100 EDT when I arrived at the oval it was mostly cloudy with altostratus. And 45 minutes later I was hard pressed to find a patch of open sky. Now it is closely packed broken stratocumulus. The temperature is a little cooler tonight than it has been recently and the air feels more humid as well. There is no air movement. Transparency Poor Seeing
Instruments	Canon 15x50 IS binocular - Charlie
Observing Party	Charlie Ridgway

Target ISS Visible Pass Constellation Category Satellite Time 20060817.2113 EDT Comments Appeared from behind an apartment building in behind a layer of cirrostratus and passed overhead near the zenith at Mag -2.6.

Target Iridium 23 Flare Constellation Peg Category Satellite Time 20060817.2142 EDT Comments :Not Seen By this time I had given up on this one and was logging it as a not seen when I looked up and saw it flaring through a thin spot in the broken stratocumulus clouds. It was just a momentary bright flash of light.

Target Iridium 59 Flare Constellation Per Category Satellite Time 20060817.2247 EDT Comments Not Seen Only 9° off the horizon in the NE where by view is blocked by apartments even if the sky had cleared off.