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Discovery [1] | |
---|---|
Discovered by | Holman et al. |
Discovered | in 2000 |
Mean orbital elements [2] | |
Epoch 2000 Feb. 26.00 | |
Semi-major axis | 16.182 |
Eccentricity | 0.4770 |
Inclination | 34.207° * |
Orbital period | 783 d (2.15 yr) |
Physical characteristics | |
Mean diameter | 32 km[3] ** |
Albedo | 0.04 [3] assumed |
Color | light red (varying) B-V=0.89 R-V=0.50[4] |
|
Albiorix (IPA: [ælˈbaiʊrɪks]) is a prograde irregular satellite of Saturn. It was discovered by Holman, et al. in 2000, and given the temporary designation S/2000 S 11. [5] Albiorix is the largest member of the Gallic group of irregular satellites. Its name derives from one of the Celtic names for the god of tribal unity, better known as Toutatis.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/2/2c/TheIrregulars_SATURN_PRO_GROUPS.svg/300px-TheIrregulars_SATURN_PRO_GROUPS.svg.png)
Albiorix orbits Saturn at a distance of about 16 Gm and it's diameter is estimated at 32 kilometers, assuming an albedo of 0.04.
The diagram illustrates its orbit in relation to other prograde irregular satellites of Saturn. The eccentricity of the orbits is represented by the yellow segments extending from the pericentre to the apocentre.
Given the similarity of the orbit's elements and the homogeneity of the physical characteristics with other members of the Gallic group, it was suggested that these satellites could have a common origin in the break-up of a larger moon.[5][4]
Varying colours revealed recently, suggest a possibility of a large crater, leading to an alternative hypothesis that Erriapo and Tarvos could be fragments of Albiorix following a near break-up collision with another body.[6]
Resonant. Inverse color scheme test
[edit]![](http://upload.wikimedia.org/wikipedia/commons/thumb/1/1c/TheResonantTNO_90AU.svg/800px-TheResonantTNO_90AU.svg.png)
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Old and new TNO
[edit]![](http://upload.wikimedia.org/wikipedia/commons/thumb/c/c0/TheTransneptunians_73AU.svg/800px-TheTransneptunians_73AU.svg.png)
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![](http://upload.wikimedia.org/wikipedia/commons/thumb/1/1f/TheTransneptunians_80AU.svg/800px-TheTransneptunians_80AU.svg.png)
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See also higher resolution (richer content).
![](http://upload.wikimedia.org/wikipedia/commons/thumb/e/ed/TheTransneptunians_73AU_x4.svg/200px-TheTransneptunians_73AU_x4.svg.png)
High resolution TNO
[edit]![](http://upload.wikimedia.org/wikipedia/commons/thumb/e/ed/TheTransneptunians_73AU_x4.svg/800px-TheTransneptunians_73AU_x4.svg.png)
Misc formula sandbox
[edit]binary trans-Neptunian object
[edit](wishlist)
In astronomy, a binary trans-Neptunian object, or trans-Neptunian binary (TNB) is a system of two components orbiting their barycentre (the common centre of mass) while the system as a whole orbits the Sun beyond the orbit of Neptune.
Binary systems has been known for the stars and for the main-belt asteroids (since the observation of Ida) and more recently for the trans-Neptunian objects and Centaurs.
Significance
[edit]The binaries are crucial as the determination of its orbits provides the system mass leading to other physical characteristics, including density, constraints on the composition etc. In addition, the frequency of the binaries provide constraints for the scenarios of origin of the solar system. Finally, depending on the orientation of the system as seen from Earth, mutual events bring additional data helping a better determination of the size, albedo and even physical composition.
Discovery
[edit]The first trans-Neptunian binary was discovered … in 2001. Arguably, using today’s terminology, this was the second discovery after that of Charon, the largest satellite of Pluto in 1978.
Around 40 discoveries followed (as of 2007) to make the binaries from the rare into quite common occurrence.
Definition
[edit]Binary TNOs (TNB), as binary asteroids, lack a widely accepted precise definition; when one components (called primary) is significantly larger than the second (called secondary) and the barycentre is inside the primary, the secondary component is typically referred to as a “satellite” or “moon”. When the barycentre is outside the primary (e.g. Charon / Pluto) the system is sometimes referred to as true binary. Binary system is a special case of a “multiple” system; e.g. Pluto system is sometimes referred to as quadruple system[ http://arxiv.org/abs/astro-ph/0512599]
Known objects
[edit]More than 40...
Frequency
[edit]A number of studies were carried out (e.g. [2], [3]) but the these are formation-model dependent and frequency in the total population makes little sense [4]. For specicif populations, example for the classical KB... Observational limitations and bias (close binaries are more difficult to detect) make general statement meaningless.
Close and wide binaries
[edit]Beyod the large TNOs (Pluto, Haumea) only a few orbits are known, ranging from close (or even contact) binaries and to wide (large separation).
Examples in both categories...
Some studies suggest that the number of close binaries, more difficult to detect, should be bigger than wide binaries [0].
Densities
[edit]Medium (large TNOs)
Less than ice (small) (refs)!
Formation
[edit]A number of scenarios have been postulated for the formation of binaries, including capture and collision. Collisional origin is accepted for some so called low and medium momentum systems (Pluto and its moons, Haumea and its moons) while the capture remains a viable candidate for widely separated systems.
The formation by capture requires a third body to damp the excess momentum. In one model the capture happens inside the Hill sphere of a third object. Another, requires ...
External links
[edit]References
[edit]- ^ Discovery Circumstances (JPL)
- ^ Mean orbital parameters from JPL
- ^ a b Scott Sheppard pages
- ^ a b Grav, Tommy; Holman; B. Gladman; Aksnes, Kaare Photometric survey of the irregular satellites, Icarus, 166,(2003), pp. 33-45. Preprint
- ^ a b B. Gladman, P. Nicholson, Burns, JJ Kavelaars, Brian G. Marsden, Holman, Grav T. et al. Discovery of 12 satellites of Saturn exhibiting orbital clustering., Nature, 412 (2001), p. 163
- ^ Tommy Grav and James Bauer A deeper look at the colors of Saturnian irregular satellites, Preprint
- Ephemeris from IAU