Carpo , also , is a small outer

natural satellite A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite). Natural satellites are often colloquially referred to as ''moons ...

Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandt ...

. It was discovered by a team of astronomers from the

University of Hawaii A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. ''University'' is derived from the Latin phrase ''universitas magistrorum et scholarium'', which ...

led by

Scott S. Sheppard Scott Sander Sheppard (born 1977) is an American astronomer and a discoverer of numerous moons, comets and minor planets in the outer Solar System. He is an astronomer in the Department of Terrestrial Magnetism at the Carnegie Institution for Scie ...

in 2003, and was provisionally designated as until it received its name in early 2005. It was named in March 2005 after Carpo, one of the

Horae In Greek mythology the Horae () or Horai () or Hours ( grc-gre, Ὧραι, Hōrai, , "Seasons") were the goddesses of the seasons and the natural portions of time. Etymology The term ''horae'' comes from the Proto-Indo-European ("year"). ...

, and a daughter of

Zeus Zeus or , , ; grc, Δῐός, ''Diós'', label=genitive Boeotian Aeolic and Laconian grc-dor, Δεύς, Deús ; grc, Δέος, ''Déos'', label=genitive el, Δίας, ''Días'' () is the sky and thunder god in ancient Greek religion, ...

(Jupiter). Carpo has a diameter of about for an

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse logarithmic astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it we ...

of 16.2. Like all irregular moons of Jupiter, Carpo's orbit is highly variable over time due to gravitational

perturbations Perturbation or perturb may refer to: * Perturbation theory, mathematical methods that give approximate solutions to problems that cannot be solved exactly * Perturbation (geology), changes in the nature of alluvial deposits over time * Perturbatio ...

by the Sun and other planets. On average, Carpo's orbit has a

semi-major axis In geometry, the major axis of an ellipse is its longest diameter: a line segment that runs through the center and both foci, with ends at the two most widely separated points of the perimeter. The semi-major axis (major semiaxis) is the lo ...

of , a high

eccentricity Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off- center, in geometry * Eccentricity (graph theory) of a ...

of 0.42, and a very high

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...

of 54° with respect to the

ecliptic The ecliptic or ecliptic plane is the orbital plane of the Earth around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic agai ...

. Carpo was long thought to be an outlier prograde satellite not part of any group, until S/2018 J 4 was found. The orbital

of satellites such as Carpo is limited by the

Kozai effect In celestial mechanics, the Kozai mechanism is a dynamical phenomenon affecting the orbit of a binary system perturbed by a distant third body under certain conditions. It is also known as the von Zeipel-Kozai-Lidov, Lidov–Kozai mechanism, Koza ...

, which induces a periodic exchange between the inclination and

of the orbit. If the inclination is large enough, the eccentricity can in turn grow so large that the

periapsis An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any ellip ...

of the satellite (called the ''

perijove An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any elli ...

'' in the case of moons of Jupiter) would be in the immediate vicinity of the

Galilean moon The Galilean moons (), or Galilean satellites, are the four largest moons of Jupiter: Io, Europa, Ganymede, and Callisto. They were first seen by Galileo Galilei in December 1609 or January 1610, and recognized by him as satellites of Jupi ...

s (Io, Europa, Ganymede and Callisto). The satellite would eventually collide with one of these, or a close encounter would eject it altogether from the Jovian system. Due to the Kozai effect, Carpo's

argument of periapsis The argument of periapsis (also called argument of perifocus or argument of pericenter), symbolized as ''ω'', is one of the orbital elements of an orbiting body. Parametrically, ''ω'' is the angle from the body's ascending node to its periap ...

never precesses and instead librates about 90° with respect to the ecliptic, which keeps Carpo's perijove always above Jupiter and its apojove below (see orbit animation below).

References

External links

Jupiter's Known Satellites
(by

) {{DEFAULTSORT:Carpo (Moon) Moons of Jupiter Irregular satellites Discoveries by Scott S. Sheppard Astronomical objects discovered in 2003 Moons with a prograde orbit