Celestia Forums

This is the third major discovery in the Kuiper belt that occured on July 29, 2005. The object tentatively named 2005 FY9 is a large KBO that orbits the sun far beyond Neptune in a wildly inclined and eccentric orbit. The orbital eccentricity is ~0.15, but the inclination is at a whopping 29?° above the plane in which most of the planets orbit our sun!

The exact size of 2005 FY9 is still uncertain, but recent data indicates an absolute magnitude of -0.3, with an albedo of ~0.59. These two figures place a maximum diameter of 2005 FY9 just below 2000km (to see for yourself, simply visit http://www.physics.sfasu.edu/astro/asteroids/sizemagnitude.html and plug in the data posted above).

In addition to distance and size data, preliminary spectrum results in a bright surface for 2005 FY9 covered in methane ice. The surface appears to be more Pluto-like in color than the distinctly grey colored 2003 UB313.

More information on this giant KBO should come soon. Stay tuned. Later!

J P

According to Mike Brown's website and other astronomers, 2005 FY9 is currently estimated to be ~1800 km in diameter, or 4/5 the size of Pluto. With an absolute magnitude of -0.3, this giant KBO would have an albedo of ~80%. If this is the case, then 2005 FY9 would easily have the highest albedo of any known KBO.

Note: I got this stuff from a summary of an abstract that is supposed to be available to the public "soon." When it becomes available, I'll post the link here. Stay tuned! Later!

J P