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RE: Sedna
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Mission to Sedna



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Kuiper Belt Object 90377 Sedna is at opposition on the 15th November, 2011.  (86.067 AU)



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90377 Sedna is a trans-Neptunian object and a likely dwarf planet discovered by Michael Brown (Caltech), Chad Trujillo (Gemini Observatory) and David Rabinowitz (Yale University) on November 14, 2003. 
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Title: Sedna and the Oort Cloud Around a Migrating Sun
Authors: Nathan A. Kaib, Rok Rokar, Thomas Quinn

Recent numerical simulations have demonstrated that the Sun's dynamical history within the Milky Way may be much more complex than that suggested by its current low peculiar velocity. In particular, the Sun may have radially migrated through the galactic disk by up to 5-6 kpc. This has important ramifications for the structure of the Oort Cloud, as it means that the solar system may have experienced tidal and stellar perturbations that were significantly different from its current local galactic environment. To characterise the effects of solar migration within the Milky Way, we use direct numerical simulations to model the formation of an Oort Cloud around stars that end up on solar-type orbits in a galactic-scale simulation of a Milky Way-like disk formation. Surprisingly, our simulations indicate that Sedna's orbit may belong to the classical Oort Cloud. Contrary to previous understanding, we show that field star encounters play a pivotal role in setting the Oort Cloud's extreme inner edge, and due to their stochastic nature this inner edge sometimes extends to Sedna's orbit. The Sun's galactic migration heightens the chance of powerful stellar passages, and Sedna production occurs around ~20-30% of the solar-like stars we study. Considering the entire Oort Cloud, we find its median distance depends on the minimum galactocentric distance attained during the Sun's orbital history. The inner edge also shows a similar dependence but with increased scatter due to the effects of powerful stellar encounters. Both of these Oort Cloud parameters can vary by an order of magnitude and are usually overestimated by an Oort Cloud formation model that assumes a fixed galactic environment. In addition, the amount of material trapped in outer Oort Cloud orbits can be extremely low and may present difficulties for models of Oort Cloud formation and long-period comet production.

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Kuiper Belt Object (90377) Sedna
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Google Earth file: Kuiper Belt Object (90377) Sedna.kmz (15kb, kmz)



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In Inuit mythology, Sedna (Inuktitut Sanna) is the goddess of the sea and marine animals such as the seals. A creation myth, the story of Sedna shows how she came to rule over Adlivun, the Inuit underworld. Sedna is also known as Arnakuagsak or Arnaqquassaaq (Greenland) and Satsuma Arnaa (Mother of the Deep, West Greenland) and Nerrivik (northern Greenland) or Nuliajuk (District of Keewatin, Northwest Territories).
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Kuiper Belt Object 90377 Sedna makes its closest approach to the Earth (86.372 AU) on the 17th November, 2010.


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Blobrana


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Posts: 131433
Date:
90377 Sedna
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90377 Sedna is a trans-Neptunian object and a likely dwarf planet discovered by Michael Brown (Caltech), Chad Trujillo (Gemini Observatory) and David Rabinowitz (Yale University) on November 14, 2003.
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Sedna
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The most distant object orbiting the sun has been detected. It's about 1/3 the size of the earth, 3 billion kilometres further away from the Sun than Pluto. This object has been provisionally named "Sedna", after the Inuit goddess of the sea. Measurements suggest that Sedna has a diameter between 1,180 to 2,360km in diameter and is a half-rock and half-ice mixture.
This would make it the biggest find in the solar system since Pluto was discovered 74 years ago.
An official NASA announcement was made at 1800 UTC 15th March. It was discovered by astronomers using California's Mount Palomar Observatory on November 14, 2003.
The Spitzer Space Telescope and the Tanagra Observatories made follow-up studies.
Although Sedna could be a so-called Kuiper Belt object, its discoverers are unsure if it is as they consider it unlike any other object yet found. The importance of Sedna is that it is the first such world discovered in a 'normal' orbit. Other similar but smaller worlds, like Quaoar and Varuna, originated in the Kuiper Belt but have since been perturbed into different orbits. The discovery will reignite the debate about what is a planet. Sedna, or 2003 VB16, as it was originally designated, will have follow-up studies to measure its thermal radiation to determine how hot it is, and therefore provide a better estimate of its size. The planetoid is usually cold; the temperatures never rise above minus 240 degrees Celsius. There was indirect evidence that Sedna had a moon - the slow rotation - but this not the case . A notable feature of Sedna is its reddish colour and it's very shiny. .
It was 13 billion kilometres away, in the Constellation Cetus (Position J2000: RA: 3h15m10s Dec: +5d38m15s), and over the next 72 years it will become brighter and closer, after which it will head out into the Oort cloud again, reaching 130 billion kilometres from the Sun, taking 10,500-years for one solar orbit.


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Update: 1st August 2005
spacer.gif 2003 EL61 & 2003UB313

2003 EL61 and 2003UB313

Dr. Michael Brown, associate professor of planetary astronomy, California Institute of Technology, Pasadena, California, presented his discovery and major findings of the most distant object ever detected orbiting the Sun, at a press media teleconference held on the 29 th July.
He and his colleagues made the observations as part of a NASA-funded research project.

With the current temporary name 2003UB313, the KBO was discovered in an ongoing survey at Palomar Observatory's Samuel Oschin telescope by astronomers Mike Brown (Caltech), Chad Trujillo (Gemini Observatory), and David Rabinowitz ( Yale University). They have proposed a name (lilah) to the IAU and will announce it when that name is accepted.

And It is bigger than Pluto!!!



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