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1222 Tina, provisional designation 1932 LA, is an eccentric, metallic asteroid from the outer region of the asteroid belt, about 21 kilometers in diameter. It was discovered by Belgian astronomer Eugène Delporte at Royal Observatory of Belgium in Uccle on 11 June 1932.〔 The X-type asteroid orbits the Sun at a distance of 2.1–3.5 AU once every 4 years and 8 months (1,707 days). Its orbit shows an eccentricity of 0.25 and is tilted by 20 degrees to the plane of the ecliptic. It has a rotation period of 13.4 and 17.2 hours as observed at the Palmer Divide Observatory ''(also see )'' and by Pierre Antonini, respectively.〔〔 It has an albedo of 0.16–0.31, according to the surveys carried out by the space-based satellites IRAS, Akari, and WISE. This would place the body into the subgroup of metallic M-type asteroids (Akari and WISE, albedo lower than 0.02) or into the E-type subgroup (IRAS, albedo above 0.30).〔〔〔 The body is the namesake of the Tina family a group of 17–89 asteroids that form a small, well-defined asteroid family, which share similar spectral properties and orbital elements; hence they may have arisen from the same collisional event of two larger parent bodies. All members have a relatively high orbital inclination.〔〔 The Tina family is unique because of its resonant nature: all its members are in anti-aligned librating states of the ν6 secular resonance, i.e., the longitudes of pericenter of the asteroids follow the longitudes of pericenter of Saturn by 180 degrees. This orbital configuration protects the asteroids from achieving high eccentricities and experiencing close encounters with terrestrial planets, forming a stable in a region strongly perturbed by the ν6 secular resonance. The family is estimated to be relatively young, about million years old, and will most likely disperse to unstable regions in timescales of 200 million years.〔 The minor planet was named after "Tina", a female amateur astronomer and friend of the discoverer.〔 == References == 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「1222 Tina」の詳細全文を読む スポンサード リンク
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