Pluto and Charon: The "Double Planet"
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ZC-Pluto_s Map-HST-PIA00825_modest.jpgA "Map" of Pluto, from HST86 visiteCaption NASA originale:"The two smaller inset pictures at the top are actual images from HST; North is up. Each square pixel (picture element) is more than 160 Km across. At this resolution, HST discerns roughly 12 major "regions" where the surface is either bright or dark. The picture was taken in blue light when Pluto was at a distance of about 3 BMs from Earth".
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ZD-Pluto.jpgPluto and the stars around...90 visiteUn'immagine, a nostro parere, altamente suggestiva di Plutone e del campo stellato che lo circonda. Anche questo frame è stata estratto dalla "2MASS Atlas Image Gallery at IPAC".
Plutone è l'oggetto posizionato ESATTAMENTE AL CENTRO della fotografia.
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ZE-Pluto-fict-map.jpgFictional Map of Pluto86 visiteLa superficie di Plutone - così ben dettagliata - è frutto dell'immaginazione dell'Artista; altrettanto, invece, non si può dire del colore del paesaggio il quale - a quanto ci è stato detto - è coerente con quanto pensano gli Scienziati che hanno osservato e fotografato Plutone usando le spettacolari ottiche dell'HST, nonchè le tecniche di ripresa maggiormente efficaci ed all'avanguardia. Le stesse tecniche, guarda caso, che ci permettono di dire che la superficie della lontanissima Sedna è rossiccia, ma che non risultano adeguate a chiarire il mistero dei "colori" del vicino - in tutti i sensi - Marte.
Curioso, non credete?!?
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ZJ-Charon.gifCharon (the surface - speculation)54 visiteOriginal caption:"This image shows 4 views of Pluto's moon Charon.
The images are centered in 0° Lat. and 0° (top-left), 90° (top-right), 180° (bottom-left) and 270° (bottom-right) Long.
The images are based on photometric measurements of Marc Bouie/Lowell Observatory".
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ZK-CharonMap.jpgThe surface of Charon (speculation)53 visiteOriginal caption:"This is the first surface map of Charon, the moon of the Solar System's most remote planet, Pluto. The map is only based on photometric measurements and it covers the entire surface of the moon. (Courtesy A.Tayfun Oner, based on pictures courtesy of Marc Buie/Lowell Observatory)
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ZL-The Moons of Pluto.jpgNew "moons" for Pluto? Early news (first picture at LR)54 visiteTwo small moons have been discovered orbiting Pluto, bringing the Planet's retinue of known satellites to 3 and leaving scientist to wonder how it could be.
The newfound moons orbit about 27.000 miles (44.000 Km) from Pluto, more than twice as far as Charon, Pluto's other satellite, and they are 5000 times dimmer than Charon.
Preliminary observations suggest they are in circular orbits around Pluto and in the same plane as Charon, said Hal Weaver of the Johns Hopkins Applied Physics Laboratory.
"That suggests they probably formed at the same time as Charon" Weaver told SPACE.com in a telephone interview. NASA planned a teleconference with reporters to announce the discovery.
While scientists had predicted there might be more moons, the newfound setup is surprising nonetheless, in part because Pluto is smaller than our own Moon.
"It's almost like a mini Solar System" Weaver said.
How can something about 70% the size of Earth's Moon have all these satellites? How can that happen?".
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ZM-The Moons of Pluto.jpgNew "moons" for Pluto? Early news54 visiteThe leading theory for the formation of Charon involves a large object striking Pluto. The debris from that collision could have formed the two smaller moons, Weaver speculates. It can't be ruled out that they might have been captured into the System, but that seems very unlikely, he said. The two new moons are between 30/40 and 100/125 miles (48/64 to 160/200 Km) in diameter. There is not enough data to pin their size down exactly, however. The moons were found using the HST.
The moons are catalogued as S/2005 P1 and S/2005 P2 for now.
Once they are confirmed, the discoverers will suggest names, to be approved by the IAU (International Astronomical Union).
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ZN-The Moons of Pluto.jpgNew "moons" for Pluto? Early news78 visiteDunque il Sistema (Binario) Plutone-Caronte starebbe per diventare (o forse è già ufficiosamente diventato) un Sistema Quaternario il quale fa, letteralmente, a pugni con le nostre stra-consolidate idee e speculazioni sull'origine e le caratteristiche di Plutone e dei piccoli Corpi Celesti trans-Nettuniani.
Un plauso al Sito "Multidimensione", sul quale abbiamo rintracciato la notizia in prima battuta, e complimenti allo "Chef" (che presumiamo essere il Web-Master).
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ZO-Pluto System.jpgPluto's System: Facts, Data, Men and early Picture53 visiteFast Facts — Recent Technical information (Oct. 2005)
Object Name: Pluto
Object Description: Planet
Distance: Although its orbit is highly eccentric, Pluto's average distance from the Sun is 39,44 Astronomical Units (A.U.) or roughly 3,6 BMs (such as about 5,9 BKM).
Dimensions: Pluto has a diameter of roughly 1.475 miles (about 2.280 Km) at the equator.
About the Data Description: these HST data are from proposal 10427: H.A. Weaver (JHU/APL), M.W. Buie (Lowell Obs.), S.A. Stern, J.R. Spencer, E. Young, and L.A. Young (SwRI); and proposal 9391: M.W. Buie and W.M. Grundy (Lowell Obs.), E. Young, L.A. Young, and S.A. Stern (SwRI). M. Mutchler (STScI) and A.J. Steffl (SwRI) are also on the science team.
Instrument: ACS/WFC ACS/HRC
Exposure Date(s): May 15/18, 2005 various dates in 2002 and 2003
Filters: F606W (V) F475W (B) and F555W (V)
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ZP-Pluto System 01.jpgPluto's System: first scheme of the possible orbits53 visiteHubble reveals two previously undetected satellites likely orbiting Pluto in the same plane as Pluto's moon, Charon. The two objects are estimated to have diameters between 30/40 and 100/125 miles (such as from about 48/64 and 160/200 Km) and both orbit roughly 27.000 miles (about 43.000 Km) from Pluto.
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ZQ-Pluto System 02.jpgPluto's System: the observations of June 200253 visiteA careful search of HST images taken with the ACS/HRC on June 14th, 2002, reveals two objects that are consistent with the expected locations of the newly-discovered satellites. One image (top) was taken in yellow light (555 nm) and the other (bottom) was taken in blue light (475 nm). The ellipse shows the orbital path of the new satellites derived from the May 2005 HST observations. The satellites should lie somewhere along this ellipse and, indeed, there are two objects along the predicted path, thus confirming the 2005 observations.
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ZR-Pluto System 04.jpgPluto's System: second scheme of the possible orbits53 visiteAlthough a full orbital solution for the satellites cannot be determined from only two HST measurements, it turns that their paths closely follow that expected for objects orbiting the Pluto System's barycenter in a perfect circle in the same plane as Charon's orbit. In this diagram, the barycenter is the dot in the center, Pluto's orbit is the smallest ellipse, Charon's orbit is the next ellipse (its position on May 15 and May 18 are indicated by the filled and open circles, respectively), an orbit that is consistent with P2's measured positions is next, followed by an orbit that is consistent with P1's measured positions. For both of the latter cases, the filled squares are positions on May 15 and open squares are positions on May 18.
Note: the so-called "projection effects" cause the circular orbits to look elliptical on the plane of the sky.
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