Pluto and Charon: The "Double Planet"
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ZS-Pluto System 00.jpgPluto's System: the movements of the bodies in three days53 visiteThese HST images, taken by the Advanced Camera for Surveys, reveal Pluto, its large moon Charon, and the planet's two new candidate satellites. Between May 15 and May 18, 2005, Charon, and the putative moons, provisionally designated P1 and P2, all appear to rotate counterclockwise around Pluto. P1 and P2 move less than Charon because they are farther from Pluto and therefore would be orbiting at slower speeds. P1 and P2 are thousands of times less bright than Pluto and Charon. The enhanced-color images of Pluto (the brightest object) and Charon (to the right of Pluto) were constructed by combining short exposure images taken in filters near 475 nnmts (blue) and 555 nnmts (green-yellow). The image of the new moons were made from longer exposures taken in a single filter centered near 606 nnmts (yellow) and therefore no color information is available for them.
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ZT-2005-19-c-large_web.jpgPluto's System: the best images so far (1)53 visiteEd ora, per concludere, una nostra modesta speculazione: come avete letto e notato, gli Scienziati che stanno studiando le immagini HST, cercano (come ovvio) di ricondurre i possibili movimenti orbitali dei 2 nuovi oggetti individuati nelle immediate prossimità del Sistema Plutone-Caronte agli schemi orbitali tradizionali classici i quali prevedono, in buona sostanza, l'esistenza di un corpo centrale maggiore (il 'Parent-Planet') ed "n" corpi secondari minori ('moons' o 'satellites') che gli orbitano intorno.
Ebbene, in assenza di dati decisivi e definitivi (per ora), potremmo considerare anche un'altra ipotesi, e cioè che i due nuovi oggetti sìano essi stessi un Sistema Binario (in questo caso "puro", e cioè senza "Parent Planet") il quale si muove attorno al Sistema Plutone-Caronte.
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ZU-2005-19-b-large_web.jpgPluto's System: the best images so far (2)53 visiteSemplifichiamo: la nostra speculazione dice che i due nuovi corpi (che chiameremo P1 e P2) NON orbitano attorno a Plutone in un rapporto riconducibile al modello classico "Satellite:Parent Planet", bensì costituiscono un Sistema Binario Indipendente il quale si trova in - semplice - equilibrio gravitazionale rispetto ad un altro Sistema Indipendente.
Le prove di una simile (azzardata, ma affascinante) costruzione, le potremmo trovare solo studiando in maniera ultra-dettagliata i movimenti di P1 e P2 rispetto a Plutone e Caronte. Movimenti che, se la nostra speculazione fosse corretta, configurerebbero percorsi orbitali - dal nostro punto di vista - "completamente anomali" e riassumibili in questo schema logico:
Plutone è Parent Planet di Caronte e SOLO di Caronte il quale gli orbita attorno assecondando un'orbita circolare; P1 e P2, invece, si muovono armonicamente l'uno rispetto all'altro e, nel farlo, "orbitano" (in senso ampio) attorno al Sistema Plutone-Caronte (che diventa "Parent System").
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ZV-Pluto System-HST~0.jpgHubble Space Telescope confirms NEW MOONS of Pluto!54 visiteAnxiously awaited follow-up observations with NASA's HST have confirmed the presence of two new moons around the distant planet Pluto. The moons were first discovered by Hubble in May 2005, but the science team probed even deeper into the Pluto System last week to look for additional satellites and to characterize the orbits of the moons.
Though the team had little doubt the moons are real, they were happy to see the moons show up very close to the locations predicted from the earlier Hubble observations. The initial discovery is being reported today in this week's edition of magazine "Nature".
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ZW-Pluto & Companions.jpgNix and Hydra!54 visiteDa "NASA - Picture of the Day" del 24 Giugno 2006:"Discovered in mid-2005, Pluto's small moons were provisionally designated S/2005 P1 and S/2005 P2.
They have now been officially christened Nix and Hydra.
Compared to Pluto and its large moon Charon, at 2.360 and 1.210 Km in diameter respectively, Nix (inner moon) and Hydra (outer moon) are tiny, estimated to be only 40 to 160 Km across. Pluto and Charon are bright enough to create diffraction spikes in this HST image, but Nix and Hydra are some 5.000 times fainter than Pluto and appear only as small points of light. Still, their new names are appropriate for the distant Pluto System. In mythology, Nix was the goddess of Darkness and Night and the mother of Charon, while Hydra was a nine headed monster and is now orbiting the Solar System's 9th planet.
Of course Nix and Hydra also share initials with the pluto-bound spacecraft New Horizons".
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ZX-Pluto_s System.jpgPluto's System61 visiteThis pair of NASA HST images shows the motion of Pluto's satellites between February 15th and March 2nd, 2006.
Both images were taken through a red filter (F606W) using the High Resolution Channel (HRC) of the Advanced Camera for Surveys (ACS). During this 15-day period, Pluto's newly-discovered satellite S/2005 P 2 (P2 for short) moved counterclockwise from the noon position to the 5 o'clock position, while the other newly-discovered satellite S/2005 P 1 (P1 for short) moved counterclockwise from the 1 o'clock position to the 7 o'clock position. During that same period, Pluto's much larger and closer moon, Charon, started near the 2 o'clock position, made more than two complete counterclockwise revolutions around Pluto and ended up near the 10 o' clock position. The motions of P1 and P2 confirm that these satellites are orbiting Pluto in the same plane as Charon's orbit, as expected if all the 3 moons were created during a single - and gigantic - impact event.
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ZY-Pluto_s System.jpgThe "colors" of Pluto's System62 visiteThe latest NASA HST images of Pluto's two newly discovered satellites reveal that the new moons have the same color as Charon.
All three of Pluto's satellites reflect the Sun's light equally across the visible spectrum and have essentially the same color as Earth's moon. Pluto, in contrast, has a reddish hue.
The common color of the moons further reinforces the idea that all three moons were born from a single titanic collision between Pluto and another similarly sized Kuiper Belt object billions of years ago.
The color exposures were made on March 2nd in both red (F606W) and blue (F435W) filters using Hubble's Advanced Camera for Surveys. The Pluto team hopes to make further observations in more color filters to more precisely characterize the moons.
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ZYZ-Pluto_s System.2jpg.jpgThe "colors" and a Schematic of Pluto's System71 visiteThe new HST/ACS observations made on March 2nd reveal that all three of Pluto's satellites are neutrally colored, unlike reddish Pluto itself. Pluto's reddish color is believed to be due to reddening agents created by the effects of sunlight acting on its Nitrogen and Methane surface ices. Charon's surface is known to consist primarily of water ice; the similar color of P1 and P2 may indicate they too have water ice surfaces.
The color similarity of Pluto's two small satellites to one another and to Charon is consistent with their all having been born as a result of a single giant impact, as previously indicated by their orbits and Charon's large mass.
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ZYZ-Q-PlutoLatestColors.jpgThe "true" colors of Pluto (another interpretation)58 visiteUno studio sui possibili colori autentici di Plutone, realizzato dal bravo e modesto Ricercatore Don Davis, di cui abbiamo già apprezzato svariati studi ed elaborazioni sui "Colori del Sistema Solare" (Marte e Venere, in maniera particolare, sono - secondo noi - i suoi lavori più belli e riusciti).
Caption originale:"Pluto seems to have intriguing surface details, with pronounced contrast between white and yellow brown Regions. These regional contrasts have been largely detected by measurements of light changes as Pluto was eclipsed by its large satellite Charon, in the late 1980's. The albedo of Pluto ranges from 0,49 to 0,66, while darker more neutral colored Charon averages about 0,37".
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ZYZ-R-Pluto.jpgPluto53 visitenessun commento
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ZYZ-S-Pluto-P4-HST.jpgMore Moons for Pluto!101 visiteCaption NASA:"Nix and Hydra were first introduced to human eyes in Hubble Space Telescope images from May 2005, as Pluto's second and third known moons. Now Hubble images have revealed a fourth satellite for the icy, dwarf Planet.
Provisionally designated P4, it completes an orbit of Pluto in about 31 days. Presently Pluto's smallest and dimmest known moon, P4 is estimated to be 13 to 34 Km across. The newly discovered satellite was first spotted in Hubble observations from June 28, 2011, and later confirmed in a follow-up on July 3 and July 18. These two panels are composites of both the short and long exposures that include brighter Pluto itself along with Pluto's largest moon Charon.
Camera noise and image artifacts also show up in the long exposure segments. The Hubble observations were made while searching for faint Rings around the distant world in support of NASA's New Horizons mission, set to fly by the Pluto system in 2015".MareKromium
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ZZ-New Horizon.jpgLet's go to Pluto!!!70 visiteDestination: Pluto. The New Horizons spacecraft roared off its launch pad at Cape Canaveral in Florida, USA, last week toward adventures in the distant Solar System. The craft is one of the fastest spaceships ever launched by humans, having passed the Moon only 9 hours (!) after launch and is on track to buzz Jupiter in early 2007.
Even traveling over 75.000 Km per hour, the New Horizons craft will not arrive at Pluto until 2015.
Pluto is the only remaining planet that has never been visited by a spacecraft or photographed up close. After Pluto, the robot spaceship will visit one or more Kuiper Belt Objects orbiting the Sun even further out than Pluto.
In the picture, the New Horizons craft launches into space atop a powerful Atlas V rocket.
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