Overview

Bebhionn, designated Saturn XXXVII and provisionally S/2004 S 11, is one of Saturn's small irregular satellites. With an estimated diameter of roughly 6 kilometres, it is much smaller than the planet's major moons and appears as a faint, distant object in telescopic surveys. Bebhionn is grouped with other prograde irregular moons of Saturn and contributes to the population of captured or collisionally produced bodies orbiting far from the planet.

Orbital characteristics

Bebhionn orbits Saturn at an average distance of about 16,898,000 kilometres and completes one orbit in approximately 820.13 days. Its orbit is moderately eccentric (about 0.333) and inclined some 41° to the ecliptic, which corresponds to about 18° relative to Saturn's equatorial plane. These orbital parameters place Bebhionn among the prograde irregular satellites rather than the nearer regular moons and are recorded in the published orbital element sets for Saturnian satellites (orbital data).

Physical properties

As a small irregular satellite, Bebhionn is expected to be non-spherical and to have a dark surface, characteristics common to distant moons thought to be of captured origin. Direct measurements of its composition, rotation period and surface features are not available; such details are difficult to obtain because the object is faint and small. Estimates of diameter come from its brightness combined with typical assumed reflectivities for similar bodies.

Discovery and observation

The discovery of Bebhionn was announced on 4 May 2005 after observations made between 12 December 2004 and 9 March 2005. The team credited with the discovery included Scott S. Sheppard, David C. Jewitt, Jan Kleyna and Brian G. Marsden. Contemporary notices and listings by the discoverers and survey teams document the observational work and follow-up that established Bebhionn's orbit (discovery announcement, observational record).

Name and cultural origin

In April 2007 the moon received the name Bebhionn, derived from Bébinn (also spelled Beibhinn), a figure from early Irish mythology. The name follows the convention of naming Saturnian moons after mythological figures associated with the Roman god's namesake cultures. In myth, Bébinn is often portrayed as a beautiful supernatural woman sometimes linked with aspects of birth and womanhood; the chosen form of the name conforms to the International Astronomical Union's naming practices for irregular satellites.

Context and significance

Bebhionn is of interest mainly as part of the broader population of Saturn's irregular satellites. These small bodies help astronomers understand capture processes, collisional histories in the outer Saturnian system, and the origins of satellite groups that share similar orbits. Continued observations, especially using larger telescopes or spacecraft data where available, can refine its orbit, reveal rotation and shape, and test hypotheses that members of the same orbital group derive from a common progenitor.

  • Provisional designation: S/2004 S 11
  • Mean orbital distance: ~16.9 million km
  • Orbital period: ~820.13 days
  • Approximate diameter: ~6 km