* Astronomy

Blobrana · L

RE: Pluto

Blobrana · L

NASA will hold a news media teleconference at 18:00 GMT (13:00 EST) on the 4th February, 2010, to discuss the latest Hubble images of the distant dwarf planet Pluto.

Blobrana · L

Pluto's 80th "Anniversary"

On January 23, 1930, a camera at the Lowell Observatory in Flagstaff, Arizona, took the first of two pictures that would add [at least for a while] a ninth planet to our solar system.
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Blobrana · L

Title: Extinction layer detected by the 2003 star occultation on Pluto
Authors: Pascal Rannou, Georges Durry

A star occultation by Pluto was monitored in August 2003 by several telescopes, at several wavelengths between 0.7m and 2.23m. Besides information concerning pressure and temperature profiles, this observation revealed a chromatic effect in the light transmitted through the atmosphere at the limb. It was attributed to an extinction layer produced by spherical particles of about 0.2 m, and it was suggested that such large particle size may be due to fractal particles as on Titan. In this paper, we use an aerosol microphysical model to estimate if such extinction could be due to photochemical aerosols only. We use the case of Titan to scale the haze production rate on Pluto and we show that the chromatic effect is not likely to be produced in this way. We then study how a troposphere in Pluto's atmosphere could generate condensation droplets. We conclude that such an extinction layer is produced by condensation droplets that potentially could grow as large as observed. We find that only N2 and CO are able to condense easily. CH4 probably does not condense or, if it does, it needs to reach a very high saturation ratio and, in any case, is supersaturated on Pluto. Noteworthily, a similar layer was observed on Triton by Voyager. Finally, at the end of the paper we discuss which are the conditions to detect a chromatic effect for submicrometer to micrometer particles in future observations.

Source

Blobrana · L

Pluto still not a planet after astronomy meeting
An international astronomy meeting ended Thursday in Rio de Janeiro, and Pluto is still not a planet. The closing ceremonies of the 2009 International Astronomical Union (IAU) concluded with nary a peep about the planetary brouhaha that saw walk-outs and table-banging three years ago at the venerable astronomer's assembly, in Prague.

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Blobrana · L

Pluto likely to remain a dwarf planet
The debate surrounding the demoted planet Pluto is set to reignite as astronomers meet next week in Brazil.
The 27th general assembly of International Astronomical Union (IAU) will be the first since Pluto was stripped of its planetary status in 2006.
Despite not appearing on the official agenda, there have been rumours that Pluto supporters will push for a reopening of the debate.

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Blobrana · L

Is Pluto a planet after all?
Next week the IAU's general assembly will convene for the first time since Pluto was axed from the list of planets. Surprisingly, IAU chief Karel van der Hucht does not expect anyone to challenge the ruling made in Prague, but Pluto fans can take heart: resistance remains strong.
If Pluto is reinstated, it will probably be thanks to discovery rather than debate.

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Blobrana · L

The lower atmosphere of Pluto revealed

Using ESO's Very Large Telescope, astronomers have gained valuable new insights about the atmosphere of the dwarf planet Pluto. The scientists found unexpectedly large amounts of methane in the atmosphere, and also discovered that the atmosphere is hotter than the surface by about 40 degrees, although it still only reaches a frigid minus 180 degrees Celsius. These properties of Pluto's atmosphere may be due to the presence of pure methane patches or of a methane-rich layer covering the dwarf planet's surface.

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Blobrana · L

In August 2006 the International Astronomical Union officially demoted Pluto, putting it into the new category of "dwarf planet," a sun-orbiting object big enough to be forced into a spherical shape by gravity but not big enough to clear its own orbit. The IAU more recently deemed Pluto and two newfound bodies to be "plutoids," bright dwarf planets that circulate mostly outside Neptune's orbit. The decision was controversial and continues to generate protest, fuelled by new findings from this icy realm.

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Blobrana · L

Planetary storm over status of Pluto
Campaign seeks to overturn ruling that split the world of astronomy

The number nine has a special significance for Mark Sykes, director of the Planetary Science Institute in Tucson, Arizona. Nine is the number of planets in the Solar System, and Sykes is one of several leading astronomers who want to keep it that way.
Unfortunately, the International Astronomical Union (IAU), which adjudicates on these matters, has ruled there are no longer nine planets in the Solar System, after a decision two years ago to downgrade Pluto to the lowly status of a "dwarf planet".

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