Another One???
Hi All
First it was 2003 EL61 ~ magnitude 0.3
Then 2003 UB313 ~ magnitude -1.1
And...
2005 FY9 ~ magnitude -0.4
q = 39.154 AU, Q = 52.026AU, e = 0.141, a = 45.590 E2005-O43
...which means it is roughly ~ 2600 km across with an albedo of ~ 0.5. With a Pluto albedo of ~ 0.7 that becomes ~ 1990 km, so it's a close call. Pluto is bright from methane/nitrogen frosts, so the presence of such is plausible for 2005 FY9. But if it's darker (c.f. Sedna is ~ 0.1) then this baby is a lot bigger.
Adam