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TOPIC: 2003UB313 / The Tenth Planet


L

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2003 UB313
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Title: Direct measurement of the size of 2003 UB313 from the Hubble Space Telescope
Authors: M.E. Brown, E.L. Schaller, H.G. Roe, D.L. Rabinowitz, C.A. Trujillo

We have used the Hubble Space Telescope to directly measure the angular size of the large Kuiper belt object 2003 UB313. By carefully calibrating the point spread function of a nearby field star, we measure the size of 2003 UB313 to be 34.3 ±1.4 milliarcseconds, corresponding to a diameter of 2400 ±100 km or a size ±5% larger than Pluto. The V band geometric albedo of 2003 UB313 is 86 ±7%. The extremely high albedo is consistent with the frosty methane spectrum, the lack of red colouring, and the lack of observed photometric variation on the surface of 2003 UB313. Methane photolysis should quickly darken the surface of 2003 UB313, but continuous evaporation and redeposition of surface ices appears capable of maintaining the extreme alebdo of this body.

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L

Posts: 131433
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Xena
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The newest size measurement was released on April 11th by the Hubble Space Telescope. Astronomers waited until the planet was very close to a star and then captured a series of 28 pictures on Dec. 9 and 10, 2005, and carefully compared the sizes of the star and the planet.
They eventually determined that the planet is 2400 ± 100 km across, and reflects 86 ± 7% of the light it receives.


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This new size makes "Xena," just a little larger than Pluto.

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L

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Planet Definition
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Definition of a Planet

The IAU will publish beginning of September 2006 the definition of a "Planet".

http://www.iau.org

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L

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RE: 10th Planet
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A group of amateur astronomers has used the 2.1-meter Otto Struve Telescope at McDonald Observatory to make the first “through-the-eyepiece” sighting of the so-called tenth planet, an object orbiting the Sun in the Kuiper Belt, far beyond Pluto. The group includes members of the St. Louis and Rockland Astronomical Societies, and a few others.

The object’s official designation is 2003UB313. Its discoverers, led by Dr. Michael Brown of Caltech, have nicknamed it ‘Xena.’

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L

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2003UB313
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The Bonn group used the IRAM 30-meter telescope in Spain, equipped with the sensitive Max-Planck Millimeter Bolometer (MAMBO) detector developed and built at the MPIfR, to measure the heat radiation of 2003UB313 at a wavelength of 1.2 mm, where reflected sunlight is negligible and the object brightness only depends on the surface temperature and the object size. The temperature can be well estimated from the distance to the sun, and thus the observed 1.2 mm brightness allows a good size measurement.
It is concluded that the 2003UB313 surface is such that it reflects about 60% of the incident solar light, which is very similar to the reflectivity of Pluto.

-- Edited by Blobrana at 10:13, 2006-02-02

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L

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Date:
2003 UB313
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New observations of 2003 UB313, show it to have a diameter of some 3,000km ±300km; which is about 700km more than Pluto.

The measurement was undertaken by a German team using the 30m Iram (Institut de RadioAstronomie Millimetrique) telescope at Pico Veleta in the Sierra Nevada mountains.

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L

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RE: 10th Planet
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L

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2003 UB313
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New measurements from the Hubble Space Telescope taken in December 2005 show that the surface of 2003 UB313 is brighter than previously thought its albedo being 0.92 (compared with roughly 0.60 for Pluto).
This indicates that the 10th planet with a reflectivity of 92%, is roughly 1% larger than Pluto's assumed diameter of 2280 kilometres.. Because the surface seems so fresh, Brown speculates that the surface is regenerated by Geysers.
For a whiteness comparison fresh snow on earth has a reflectivity of 90%.

"Its reflectivity is much higher than expected. It does indicate a fresh, icy surface" - astronomer Alex Filippenko, University of California, Berkeley.

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Anonymous

Date:
RE: 2003UB313 / The Tenth Planet
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Kepler's 3rd Law
14x24x60x60=1209600 seconds
0.40 x 10^10 centimetres orbit = 4000000000

Gravity x mass x time² = 4 x pi² x radius³

39.478 =4pi²
6.6739 x 10^-8 = gravity

simplified as, mass x time² = 5.9153 x 10^6 x radius³

= 2.59e+22 kg


<Ed - Sry, Edited>

-- Edited by Blobrana at 14:34, 2005-10-11

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