Kuipers Closer To Home, 2 Trojans near Jupiter are KBOs Options

[SigurRosFan]

http://www.cnn.com/2006/TECH/space/02/01/j...mets/index.html - Asteroids near Jupiter are really comets

--- Patroclus and Menoetius [a binary KBO] are estimated to be about 76 miles (122 kilometers) and 70 miles (112 kilometers) wide, respectively. The two objects are not the first to be mistaken for asteroids: in 1999, astronomers determined that C/199 J3 was also a comet.

Because most comets are thought to form in the Kuiper Belt, a distant region of the solar system outside the orbit of Neptune, the researchers think Patroclus and Menoetius formed about 650 million years after the formation of the solar system. ---

[tedstryk]

http://www.cnn.com/2006/TECH/space/02/01/j...mets/index.html - Asteroids near Jupiter are really comets

--- Patroclus and Menoetius [a binary KBO] are estimated to be about 76 miles (122 kilometers) and 70 miles (112 kilometers) wide, respectively. The two objects are not the first to be mistaken for asteroids: in 1999, astronomers determined that C/199 J3 was also a comet.

Because most comets are thought to form in the Kuiper Belt, a distant region of the solar system outside the orbit of Neptune, the researchers think Patroclus and Menoetius formed about 650 million years after the formation of the solar system. ---

Very interesting. Of course, being so much closer to the sun would make them less-than-pristine. At the same time, it might be possible to have a flyby mission that uses solar power like Juno will at this distance, allowing a much cheaper and faster mission to reach them.

[tasp]

Pedigree of Jovian Trojans and Jovian outer moons may share some commonality.

Seems a thorough search for outer satellites close to the New Horizons flight path
for it to examine would be a very good idea.

Possibility of KBO relevant data at Jupiter (!) would be the frosting on the cake for this wonderful mission.

Instead of looking at just 6 KBOs, maybe we get lucky and see a couple more in Jupiter space.

[edstrick]

We are going to have a terminology fight in a few years. -- besides the current "Is Pluto etc a Planet?" one.

3 decades ago, solar nebula models suggested the outer asteroid belt would be significantly icy, as are most of the Galilean satellites. Ceres is starting to turn out to be a differianted mudball with an ice mantle and a dessicated ?ex-mud? crust. Move ANY of those objects close to the sun and it'll outgass and act like a "comet"

Clearly, there are multiple populations of objects formed at different distances from the sun, incorporating varying amounts of water ice (at the dry to wet to ice-dominated transition somewhere in the outer belt), and further out, incorporating varying amounts of more cryogenic compounds, starting with at least CO2 as in Phoebe's case, extending to objects formed so far out they incorporated nitrogen and other extremely low temperature ices.

These objects got tossed around and the populations got mixed, starting during accretion of the objects and of proto-gas-giants, continuing with the periods of modelled planet migration and planetisimal scattering, and continuing further since the 4 billion years back terminal lunar cataclysm impacting events, after which the solar system was in a quasi steady state with well defined populations of asteroid and Kuiper belt objects in stable orbits and others (NEO's and Centaurs and Scattered disk objects) in disturbed and often short lived orbits.

Some true KB objects got scattered inward and may be present as interlopers in Trojan asteroid and outer belt populations. Captured satellites at Jupiter and Saturn and the Trojan asteroids at Jupiter *MAY* be KB objects, but because of the low velocities needed for capture, are probably more likely to have been planetisimals from the vicinity where the planets formed. Phoebe, for example, seems more likely to have formed near Saturns orbit and been captured from there, rather than from a high velocity eccentric orbit. Granted orbit evolutions during planetary migration and planetisimal scattering are highly non-intuitive, but I doubt I'm way off base on this.

I think there will almost certainly be very significant differences between Jupiter and Saturn accretion zone planetisimals and true KB objects, and to lump all of these ice or ices (plural) rich objects into "Comet" or "KB Object" designations will confuse matters far more than they clarify them.

Outer belt asteroids, Trojans, and Jupiter and Saturns irregular outer satellites (and Jupiters inner "gravel") are likely to be tremendously valuable objects as surviving samples from parts of the planetisimal populations that were largely destroyed, unlike the inner belt and the main KB population.

The asteroid and Kuiper belts will contain interlopers scattered into their populations from now depleted parts of the nebula, but having some likely objects still near their origins will help sort out nebular history. Enstatite Chondrite meteorites, with relatively earth-like oxygen isotopes <as I recall> may be survivors from inside the current asteroid belt that were kicked out to the inner belt.

[SigurRosFan]

Another release:

- http://www.universetoday.com/am/publish/pa...ius.html?122006 - Binary asteroid in Jupiter's orbit may be icy comet from solar system's infancy