(85713) 1998 SS49
, provisional designation , is an asteroid on an eccentric orbit, classified as near-Earth object and potentially hazardous asteroid of the Apollo group, approximately in diameter. The asteroid was discovered on 29 September 1998, by astronomers of the LINEAR program at Lincoln Laboratory's Experimental Test Site near Socorro, New Mexico, in the United States. It is one of the largest potentially hazardous asteroids and has a notably low Earth-MOID of less than the distance to the Moon. Orbit and classification. is a member of the dynamical Apollo group, which are Earth-crossing asteroids. Apollo asteroids are  the largest subgroup of near-Earth objects. It orbits the Sun at a distance of 0.7–3.2 AU once every 2 years and 8 months (975 days; semi-major axis of 1.92 AU). Its orbit has a high eccentricity of 0.64 and an inclination of 11° with respect to the ecliptic. The body's observation arc begins with its official discovery observation at Socorro in September 1998. Close approaches. At about absolute magnitude 15.6, is one of the brightest and presumably largest known potentially hazardous asteroid "(see PHA-list)". It has a very low "Earth minimum orbital intersection distance" of  . On 26 November 1902, this asteroid made its closest near-Earth encounter since 1900 at a nominal distance of . The next notable close approach will be on 21 November 2022 passing at a nominal distance of . Physical characteristics. is an assumed, stony S-type asteroid. Rotation period. In 2014, two rotational lightcurves of were obtained from photometric observations by American astronomer Brian Warner at the CS3–Palmer Divide Station in California (). Lightcurve analysis gave a rotation period of 5.370 and 5.66 hours and a brightness variation of 0.18 and 0.06 magnitude, respectively (), one of which gave an alternative period solution  of hours. In April 2016, the EURONEAR lightcurve survey measured a period of 5.398 hours with an amplitude of 0.12 magnitude (). Diameter and albedo. Surveys contrast: of the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer. These measure the object as between 2 and 3.484 kilometers lengthways ("in diameter") and to have an albedo (optical wavelength reflectivity) between 0.076 and 0.237. The "Collaborative Asteroid Lightcurve Link" assumes a stony typical albedo of 0.20 to calculate the diameter as 2.25 kilometers and an absolute magnitude of 15.6. Numbering and naming. This minor planet was  numbered by the Minor Planet Center on 30 August 2004. As of 2018, it has not been named.