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From: TerryMoselaol.com
Date: Fri, 29 Jul 2005 16:33:14 EDT
Subject: Pluto's little brother....
Hi all,
It's great to have some of the world's leading experts in certain subjects
here to keep us up to date!
I've just got the following hot news from Prof Alan Fitzsimmons at QUB,
indicating that the object is likely to be smaller than Pluto.
But it's equally interesting that it has been found to have a Moon, and that
some of the better equipped Irish amateurs might be able measure the light
curve, or at least detect the variation....
..............................................................................
...................................
"Hi Terry,
A very bright TNO was announced earlier today by the MPC and given the
designation 2003 EL61. This is the object at the positions you listed in your
earlier E-mail. It has already been studied by MIke Brown and Colleagues, and
this team has already found these important details.
1. It has a moon, seen at Keck with adaptive optics and a laser guide star
system. The moon has an orbital period of 49 days and orbits at a distance of
49,500km from the object. This gives the mass as approximately 32% that of
Pluto.
2. It has a rotation period of only 3.89 hours as seen from a double- peaked
lightcurve.
Also, the amplitude of the lightcurve implies an axial ratio of 1.4 - this
object is nowhere
near spherical (albedo markings are unlikely to be the cause as the
lightcurve is very
symmetrical). I would think that this lightcurve might be measurable by
amateurs.
3. Spectra show clear signs of water ice on the surface.
4. Spitzer was used to observe it, and word is it didn't see it. If so, the
albedo will be large
and it probably has a smaller diameter than Pluto.
All the best,
Alan."
..............................................................................
...................................
Clear skies,
Terry Moseley
aol.com Date: Fri, 29 Jul 2005 16:33:14 EDT Subject: Pluto's little brother.... Hi all, It's great to have some of the world's leading experts in certain subjects here to keep us up to date! I've just got the following hot news from Prof Alan Fitzsimmons at QUB, indicating that the object is likely to be smaller than Pluto. But it's equally interesting that it has been found to have a Moon, and that some of the better equipped Irish amateurs might be able measure the light curve, or at least detect the variation.... .............................................................................. ................................... "Hi Terry, A very bright TNO was announced earlier today by the MPC and given the designation 2003 EL61. This is the object at the positions you listed in your earlier E-mail. It has already been studied by MIke Brown and Colleagues, and this team has already found these important details. 1. It has a moon, seen at Keck with adaptive optics and a laser guide star system. The moon has an orbital period of 49 days and orbits at a distance of 49,500km from the object. This gives the mass as approximately 32% that of Pluto. 2. It has a rotation period of only 3.89 hours as seen from a double- peaked lightcurve. Also, the amplitude of the lightcurve implies an axial ratio of 1.4 - this object is nowhere near spherical (albedo markings are unlikely to be the cause as the lightcurve is very symmetrical). I would think that this lightcurve might be measurable by amateurs. 3. Spectra show clear signs of water ice on the surface. 4. Spitzer was used to observe it, and word is it didn't see it. If so, the albedo will be large and it probably has a smaller diameter than Pluto. All the best, Alan." .............................................................................. ................................... Clear skies, Terry Moseley
