[X] My Assistant

[Guest_PhilCo126_*]

Observations with the Spitzer telescope have discerned two rocky asteroid belts and an icy outer ring surrounding our Sun’s doppelgänger Epsilon Eridani that could have been shaped by evolving planets. Epsilon Eridani, visible to the naked eye and located just 10.5 light years away in the constellation Eridanus, is marginally smaller and cooler than our own Sun, but at just 850 million years old is providing insight into how our Solar System evolved. Epsilon Eridani has an inner rocky asteroid belt and an outer rocky belt containing around 20 times as much material also exists in the same position as Uranus.

http://www.astronomynow.com/081027Doubleas...ystemclone.html

[Decepticon]

Has this star ever been observed optically by Keck or HST?

[ngunn]

and an outer rocky belt containing around 20 times as much material also exists in the same position as Uranus.

That's a long way out for 'rocky'. How do they know it's rocky?

Separate note -
There was an interesting presentation in the recent DPS conference (I think in the special session making the case for a dynamical definition of the term ''planet") in which it was stated that extrasolar planetary systems are expected to be 'full', with major planet orbits as close together as dynamical stability allows out to a certain distance, and that where a planet does appear to be missing a swarm of minor bodies is expected in every case. Several systems were cited as conforming to this picture.

[Guest_PhilCo126_*]

Talking about Asteroid belts & Oort Cloud:

Astronomers calculated that the mass of the Kuiper Belt eroded from 10 times Earth mass to only 3% of Earth's mass.
They assumed density was 1 gram per cubic centimeter but what for size did they use for the Kuiper Belt ( Edgeworth-Kuiper belt )?
Most text books describe the belt's size = from 30 AU to 55 AU ... but others as = from 30 AU to 100 AU ?
So that's quiet a difference

[Guest_PhilCo126_*]

Just wondered if Gary Berstein's calculations included the SDO - scattered disk objects ?
Meaning Kuiper Belt stretches between 30 AU and 100 AU ...