Discovered by E. F. Helin Alternative names 1982 SA · 1974 SQ2 Discovered 20 September 1982 Orbits Sun | Discovery date 20 September 1982 Absolute magnitude 13.6 Discoverer Eleanor F. Helin | |
Similar 4015 Wilson–Harrington, Sun, 6489 Golevka, 9969 Braille, 4769 Castalia | ||
3043 San Diego, provisional designation 1982 SA, is a stony Hungaria asteroid and slow rotator from the inner regions of the asteroid belt, approximately 4.7 kilometers in diameter. It was discovered by American astronomer Eleanor Helin on 30 September 1982, at the U.S. Palomar Observatory in California.
The bright E-type asteroid is a member of the Hungaria family, which form the innermost dense concentration of asteroids in the Solar System. The asteroid orbits the Sun at a distance of 1.7–2.1 AU once every 2 years and 8 months (977 days). Its orbit has an eccentricity of 0.11 and an inclination of 22° with respect to the ecliptic. The first observation was taken at Crimea–Nauchnij in 1974, extending the asteroid's observation arc by 8 years prior to its discovery.
In March 2005, a rotational light-curve for this asteroid was obtained from photometric observations by U.S. astronomer Brian D. Warner at his Palmer Divide Observatory (PDO), Colorado. It gave a long rotation period of 7002105700000000000♠105.7±0.1 hours with a brightness variation of 0.60 in magnitude (U=3-). The period was derived from a re-examined light-curve that originally gave a much shorter period of 7001307200000000000♠30.72±0.02 hours with an amplitude of 0.37 in magnitude (U=0). This previously published period was only preliminary and is now considered wrong upon re-examination.
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the asteroid measures 4.8 and 5.0 kilometers in diameter and its surface has an albedo of 0.25 and 0.28, respectively, while the Collaborative Asteroid Lightcurve Link assumes an albedo of 0.30 – a compromise value between 0.4 and 0.2, corresponding to the Hungaria asteroids both as family and orbital group – and calculates a diameter of 4.6 kilometers, based on an absolute magnitude of 13.7.
The minor planet was named for the city of San Diego, California, in appreciation of the city council's efforts to reduce the local light pollution (see dark-sky movement). Palomar mountain is located within San Diego County, California, and the astronomers at the site were concerned that the light pollution from the city would ruin their ability to use the observatory. The council had voted to use Low-Pressure Sodium (LPS) vapor lamps for their street lights. This fixture only emitted light at one wavelength, which astronomers could readily filter out. Naming citation was published on 13 July 1984 (M.P.C. 8914).