2003 Ub 313: The Incredible Shrinking Planet?, No bigger than Pluto? Options

[Guest_BruceMoomaw_*]

(Thanks to Emily Lakdawalla):

http://sciencenow.sciencemag.org/cgi/content/full/2006/127/1

[SigurRosFan]

Here's the detailed press release:

- http://www.unmannedspaceflight.com/index.p...indpost&p=39431

--- Note on reports of an HST size measurement (31.1.)

Mike Brown gave a public talk recently where he presented some preliminary results [Albedo 0.92 news] on an attempt to measure the size of UB313 with the Hubble Space Telescope. A journalist picked this up and reported it, against Mike Brown's explicit request. In response to this report Mike Brown stated on Jan 31:

"Contrary to rumors otherwise, we're just in the preliminary stages of analyzing the HST data. When we are done we should have a very precise measurement. The study that is coming out in Nature is the best info that we have for now about how big and reflective it is. The uncertainties are large, but it seems a solid result to me. I hope that we will have the HST analysis done within perhaps a month, and I'll be able to say more then." ---

[David]

Here's the detailed press release:
http://www.unmannedspaceflight.com/index.p...indpost&p=39431

Then:
"The so-called "tenth planet," announced last July to much fanfare, is a "smidge" bigger than Pluto rather than earlier estimates of 25% to 50% larger, a planetary scientist reported here on 25 January."

Now:
"Here we report observations of the thermal emission of 2003 UB313 at a wavelength of 1.2 mm, which in combination with the measured optical brightness leads to a diameter of 3,000±300±100 km; here the first error reflects measurement uncertainties, while the second derives from the unknown object orientation."

If 2003 UB313 is 3000 km in diameter, then it is 30% larger than Pluto, which is a bit above the going rate for smidges these days. If it is at the lowest end of the given range (2600 km) it is still 14% larger than Pluto.