(5587) 1990 SB

Near-Earth asteroid December 2025 yes (5587) 1990 SB #FFC2E0 H. E. Holt and J. A. Brown 16 September 1990 Palomar Observatory (675) (5587) 1990 SB 1990 UV 12 NEOAmor 21 November 2025 (JD 2461000.5) 0 3.70727 AU 1.09391 AU 2.40059 AU 0.544317 18.0410° 189.278° 87.6129° 209.583° 3.71951 y (1358.55 d) 0.264987° / d 0.31005 AU 3.251 3.57 km125 0.32125 13.89 Sq-typeColor indices:368B–V = 0.831 0.004V–R = 0.471 0.002V–I = 0.795 0.004V–Z = 0.772 0.007 5.05219 h187 –60°187 253°187 (5587) 1990 SB is an unnamed near-Earth asteroid (NEA) orbiting in the inner Solar System. It was discovered on 16 September 1990 by astronomers Henry E. Holt and J. A. Brown. An Amor asteroid, it is 3.57 km mi in size and has a highly elongated shape. It has a rotation period of 5.05 hours, spinning in a retrograde direction. History 1990 SB was discovered on 16 September 1990 by astronomers Henry E. Holt and J. A. Brown, who noted its fast motion at that time. It was observed using the 48-in Schmidt telescope at Palomar Observatory. It was given the provisional designation 1990 SB, and its discovery was announced in an International Astronomical Union Circular on 22 September. The asteroid was observed by the Crimean Astrophysical Observatory on 23 October, but it was reported as a new asteroid and given the provisional designation 1990 UV 12.44 The 23 October observation was later linked to 1990 SB by the Minor Planet Center on 4 June 1993, and the asteroid was assigned the minor planet number of 5587 that same day.123 2025, it remains unnamed. Orbit 1990 SB is classified as a near-Earth object (NEO) of the Amor class. The Amor asteroids are a group of NEOs that have semi-major axes greater than one astronomical unit (AU) and do not cross Earth's orbit. 1990 SB has a semi-major axis of 2.40 AU, taking 3.72 years to complete one orbit around the Sun. Along its orbit, its distance from the Sun varies from 1.09 AU at perihelion to 3.71 AU at aphelion, due to its orbital eccentricity of 0.54. Its orbit is inclined by 18° with respect to the ecliptic plane. Physical characteristics 1990 SB is about 3.57 km mi in size, based on thermal models using thermal-infrared observations from the Keck telescope.125 Photometric observations suggest that its shape is quite elongated, with axes ratios of a/b = 2.0 and b/c = 1.2. Its shape is also regular and symmetrical. Any concavities are not very deep; if it is a contact binary object, it is not very strongly bifurcated.192–193 The asteroid is classified as a stony Sq-type asteroid under the Bus classification scheme.117 It was previously suggested to be intermediate between the Q- and R-type asteroids after it was spectroscopically observed in 2001.365–366 Observations of 1990 SB's lightcurve, or variations in its observed brightness, indicate that it has a rotation period of 5.05 hours.187 Its spin pole points toward the ecliptic south, meaning that the asteroid rotates in a retrograde direction.187 References 2025-12-01 last obs. JPL Small-Body Database Lookup: 5587 (1990 SB) https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=5587 Jet Propulsion Laboratory 3 December 2025 (5587) = 1990 SB = 1990 UV12 https://www.minorplanetcenter.net/db_search/show_object?object_id=5587 Minor Planet Center 3 December 2025 live (4610 obs) Holt H. E. Brown J. A. Holt H. R. Olmstead C. M. Bowell E. IAUC 5098: 1990 SB; 1990c http://www.cbat.eps.harvard.edu/iauc/05000/05098.html#Item1 International Astronomical Union Circulars International Astronomical Union 22 September 1990 5098 3 December 2025 MPC 19055-19346 http://tamkin1.eps.harvard.edu/iau/ECS/MPCArchive/1991/MPC_19911121.pdf Minor Planet Center Staff Minor Planet Electronic Circular Minor Planet Center 21 November 1990 3 December 2025 live MPC 22089-22274 http://tamkin1.eps.harvard.edu/iau/ECS/MPCArchive/1993/MPC_19930604.pdf Minor Planet Center Staff Minor Planet Electronic Circular Minor Planet Center 4 June 1993 3 December 2025 live NEO Groups NASA/JPL Near-Earth Object Program Office http://neo.jpl.nasa.gov/neo/groups.html https://web.archive.org/web/20020202160655/http://neo.jpl.nasa.gov/neo/groups.html dead 2002-02-02 2012-06-04 Delbó Marco Harris Alan W. Binzel Richard P. Pravec Petr Davies John K. Keck observations of near-Earth asteroids in the thermal infrared November 2003 Icarus 166 1 116–130 10.1016/j.icarus.2003.07.002 2003Icar..166..116D Kaasalainen Mikko et al Photometry and models of eight near-Earth asteroids January 2004 Icarus 167 1 178–196 10.1016/j.icarus.2003.09.012 2004Icar..167..178K Dandy C. L. Fitzsimmons A. Collander-Brown S. J. Optical colors of 56 near-Earth objects: trends with size and orbit June 2003 Icarus 163 2 363–373 10.1016/S0019-1035(03)00087-3 2003Icar..163..363D Davies John K. et al Near-infrared spectra of 12 Near-Earth Objects January 2007 Icarus 186 1 111–125 10.1016/j.icarus.2006.08.008 2007Icar..186..111D External links 5587 5587 (5586) 1990 RE6 5587 5588 Jennabelle 005587 Category:Discoveries by Henry E. Holt Category:Discoveries by Michael E. Brown 005587 19900916