952 Caia

952 Caia /ˈkeɪə/ is a carbonaceous background asteroid from the outer region of the asteroid belt, approximately 82 kilometers (51 miles) in diameter. It was discovered by Soviet–Russian astronomer Grigory Neujmin at the Crimean Simeiz Observatory on 27 October 1916 and given the provisional designation 1916 Σ₆₁.^[14] It was named after the heroine in the novel Quo Vadis by Henryk Sienkiewicz.^[3]

Caia is a non-family asteroid from the main belt's background population. It orbits the Sun in the outer asteroid belt at a distance of 2.3–3.7 AU once every 5 years and 2 months (1,893 days). Its orbit has an eccentricity of 0.25 and an inclination of 10° with respect to the ecliptic.^[1] The first unused observation was made at the U.S Taunton Observatory (803) in 1908, when it was identified as 1908 EB, extending the body's observation arc by 8 years prior to its official discovery observation.^[14]

The body's odd provisional designation, 1916 Σ₆₁, was assigned at the discovering Simeiz Observatory during the First World War, when communication with the German Astronomisches Rechen-Institut, then in charge of assigning designations, was not possible over long periods of time. Instead, the observatory assigned their own, custom provisional designations containing the Greek letter sigma (Σ), in order to avoid multiple assignments. For simplicity, the letter sigma is often represented by the letter "S".^[1]

This minor planet was named after "Caia", a heroine in the historical novel Quo Vadis written by Polish journalist, novelist and laureate of the Nobel Prize in Literature in 1905, Henryk Sienkiewicz (1846–1916).^[3]

Caia is a carbonaceous C-type asteroid. It is also classified as a P-type asteroid by NASA's Wide-field Infrared Survey Explorer (WISE).^[9]

Two photoelectric lightcurve observations from 1980 rendered a rotation period of 7.50 and 7.51 hours (U=2/2),^[11][12] while a more recent light-curve analysis in 2004 gave a period of 3.795±0.001 hours (or half the previously determined period) with a very low brightness variation of 0.03 in magnitude (U=2), which typically indicates a nearly spheroidal shape.^[10]

According to the surveys carried out by the Infrared Astronomical Satellite, IRAS, the Japanese Akari satellite, and the WISE telescope with its subsequent NEOWISE mission, the asteroid has a diameter between 81.6 and 88.8 kilometers and a low albedo in the range of 0.040 and 0.056.^{[5][6][7][8][9]} The Collaborative Asteroid Lightcurve Link agrees with the spaced-based observations and derives an albedo of 0.051 with a corresponding diameter of 81.5 kilometers.^[4]

• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 952 Caia at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 952 Caia at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters