The moon of Jupiter – Aitne (XXXI) – was previously temporarily designated as S/2001 J11.
It was discovered in mid-December 2001 by the following team of astronomers: S.S. Sheppard
,
D.C. Jewitt
i J. Kleyna. This discovery was achieved by the 3.6-m Canada-France-Hawaii telescope atop Mauna Kea (Hawaii). You can read additional details in Minor Planet Electronic Circular (MPEC).
Aitne is one of eleven new satellites discovered since the →Voyager-2
Jupiter system fly-by which occured 22 years ago (1979). With this moon, the
team discovered also: Autonoe, Thyone, Hermippe, Eurydome, Sponde, Pasithee,
Euanthe, Kale, Orthosie and Euporie.
The name of that moon is of mythological origin. Aitne was a Sicilian nymph, one of the many conquests of Zeus...
The moon by this name is in elliptical retrograde orbit (→eccentricity
e = 0.2643) with a →semimajor axis a = 23,229,000 km. At pericenter (closest to the planet) Aitne is separated from the Jupiter a distance of q = 17,089,575 km. At apocenter (furthest from the planet) this moon is separated from the Jupiter a distance of Q = 29,368,425 km.
In future these parameters may vary due to a large orbital distance from Jupiter and the orbital motion being disturbed by the Sun and other factors. Perhaps it is a captured asteroid (with a microscopic mass: ~4.4960×1013 kg – it equals
over 163 times less than a mountain like Giewont
!),
and in future will possibly return to heliocentric orbit.
The orbital period is over 2 earthly years, which means that the average speed of its celestial motion is
only 0°29'35'' per day. When this motion was detected and compared to the changes in Jupiter's position, this body was classified as a true planetary satellite (and not a distant celestial body with its position projected near the planet).
Other obstacle in detecting this moon earlier was its brightness of only 22.7m
(almost 4.8 million times fainter than the faintest stars visible to naked eye). For comparison: Jupiter's brightness is about
–2.7m, so Aitne is shining fainter by about 25.4m.
The corresponding difference in brightness is over 14.5 billion times!
I have given some crucial data of Aitne below. Table one
contains the basic information. Whereas table two gives more detailed parametrs
of its orbit (calculated using the following formulae).
Translated by Karol Pankowski
|
Aitne
|
|---|
| Mean distance from the planet [×103 km] |
23,229.0
|
| Mean distance from the planet [planetary R] |
324.9
|
| Orbital period [days] |
730.18
|
| Orbital eccentricity [e] |
0.2643
|
| Orbit inclination [degrees] |
165.1
|
| Mean diameter [km] |
3.0
|
| Main discoverer and year of the discovery |
S.S. Sheppard 2001
|
| Visual magnitude [mag] |
22.7
|
| Mass [kg] |
~4.4960 × 1013
|
Orbital Parameters |
Pericenter
[q] |
Apocenter
[Q] |
| Distance from the planet [×103 km] |
17,089.6
|
29,368.4
|
| Distance from the planet [planetary R] |
239.0
|
410.8
|
| Angular size of the moon's orbit observed from the Earth* [degrees] |
1°33'26.93''
|
2°40'37.82''
|
|
| Angular diameter of the planet's disc as observed from the moon [degrees] |
0°28'45.77''
|
0°16'44.23''
|
| Brightness of the planet as observed from the moon** [mag] |
–10.5
|
–9.4
|
| Diameter of the moon's disc as observed from the planet's "surface" [degrees] |
0°00'00.04''
|
0°00'00.02''
|
| Brightness of the moon as observed from the planet's "surface"** [mag] |
14.9
|
16.0
|
|
Orbital velocity [km/sec] |
3.06
|
1.78
|
* This value is calculated for Jupiter at opposition (distance 628.8 million km = 4.2 AU)
** The given value of magnitude is not corrected for some decreasing factors (e.g. the changing phase of illumination)
|
See other related links:
Monde
des Monats
– CARMEGRUPPE
Jupiter's 2002 Satellites
The Astronomy Workshop – Satellite Viewer
Planetary Satellite Mean Orbital Parameters
Natural Satellite Physical Parameters
