The moon of Jupiter – S/2003 J23 –
was discovered in February 6, 2003 by S.S. Sheppard
.
The discovery was made using the 3.6-meter Canada-France-Hawaii Telescope telescope and two others: a bigger one, the 8.3 meter Subaru and a smaller 2.2 meter instrument. The three telescopes are placed atop Mauna Kea (Hawaii) and they are just a small part of the inventory at this site. As for the discovery, further details are availible in the
The International Astronomical Union Circular
(→IAU).
Similarly to Thelxinoe,
it was discovered back in 2003 but it was announced almost a year afterwards after
B. G. Marsden determined its orbit on January 31, 2004...
S/2003 J23 is a new satellite discovered since the →Voyager-2
Jupiter system fly-by which occured 24 years ago (1979).
The moon is in elliptical retrograde orbit (→eccentricity
e = 0.2738) with a →semimajor axis a = 23,566,000 km. At pericenter (closest to the planet) S/2003 J23 is separated from the Jupiter a distance of q = 17,113,629 km. At apocenter (furthest from the planet) this moon is separated from the Jupiter a distance of Q = 30,018,371 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: ~1.4987×1013 kg – it equals 490 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°29'29'' 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 23.6m
(almost 11 million times fainter than the faintest stars visible to naked eye). For comparison: Jupiter's brightness is about –2.7m,
so S/2003 J23 is shining fainter by about 26.3m.
The corresponding difference in brightness is over 33 billion times!
I have given some crucial data of S/2003 J23 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
– 
