The moon of Jupiter – Arche (XLIII) – was previously temporarily designated as S/2002 J1. It was discovered in 2002 by S.S. Sheppard. This discovery was achieved by 2.2-m telescope atop Mauna Kea (Hawaii). You can read additional details in The International Astronomical Union Circular (→IAU).
    Arche is a new satellite discovered since the →Voyager-2 Jupiter system fly-by which occured 23 years ago (1979). 
    The moon is in elliptical retrograde orbit (→eccentricity e = 0.2588) with a →semimajor axis a = 22,931,000 km. At pericenter (closest to the planet) Arche is separated from the Jupiter a distance of q = 16,996,457 km. At apocenter (furthest from the planet) this moon is separated from the Jupiter a distance of Q = 28,865,543 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 163 times less than a mountain like Giewont!), and in future will possibly return to heliocentric orbit.

    The orbital period is a somewhat less than 2 earthly years, which means that the average speed of its celestial motion is only 0°29'50'' 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 22.8^m (over 5.2 million times fainter than the faintest stars visible to naked eye). For comparison: Jupiter's brightness is about –2.7^m, so Arche is shining fainter by about 25.5^m. The corresponding difference in brightness is almost 16 billion times!