This minor planet was named for the four-armed god of protection and preservation of good, Vishnu, one of the principal deities of Hinduism. The asteroid's name was proposed by Belgian amateur astronomer and professional meteorologist Jean Meeus.[2][4] The approved naming citation was published by the Minor Planet Center on 15 July 2011 (M.P.C. 75547).[5]
Classification and orbit
Vishnu orbits the Sun at a distance of 0.6–1.5 AU once every 1 years and 1 month (398 days). Its orbit has an eccentricity of 0.44 and an inclination of 11° with respect to the ecliptic.[1] As no precoveries were taken, and no prior identifications were made, the body's observation arc begins with its official discovery observation at Palomar in 1986.[2]
Its highly eccentric orbit crosses the orbits of all inner planets except that of Mercury, which effectively makes it a Venus-crosser, Earth-crosser and Mars-crosser all at once. From 1800 to 2200, Vishnu has made and will make multiple approaches of Venus (71×), Earth (29×), and Mars (7×) within 30 gigameters. It has been observed by radar astronomy (Binzel) and the orbital solution includes non-gravitational forces.[1]
Physical parameters
In the SMASS taxonomy, Vishnu is a rare O-type asteroid, meaning it is similar to the asteroid 3628 Boznemcová, which is the best asteroid match to the spectra of L6 and LL6 ordinary chondrite meteorites. These L and LL chondrites have lower iron metal content, but higher iron oxide content in the silicates.[1]
In the early 2000s, Vishnu has been observed in the thermal-infrared by the Keck telescope on Mauna Kea, Hawaii. The asteroid measures approximately 420 meters in diameter and its surface has a high albedo of 0.520.[3] As of 2017, Vishnu'srotation period and shape remain unknown as no lightcurves have yet been obtained.[6]
