This minor planet was named by IAU's Working Group for Planetary System Nomenclature after the Greek astronomer Hipparchus (c. 190 – c. 120BC), considered to be the greatest astronomer of ancient times. Hipparchus introduced a systematic and critical approach to both theoretical and observational astronomy. He is also honored by a lunar and a Martian crater (Hipparchus and Hipparchus, respectively).[3] The official naming citation was published by the Minor Planet Center on 21 November 1991 (M.P.C. 19335).[14] The asteroid is one of several early "kilo-numbered" minor planets that were dedicated to renowned scientists or institutions including:[15]
Based on its low albedo of around 0.04–0.05 (see below), Hipparchus is likely of a carbonaceous rather than siliceous composition, among which the C-type asteroid are the most common ones in the asteroid belt.
In February 2014, a rotational lightcurveofHipparchus was obtained from photometric observations by astronomers at the Phillips Academy (I12) and HUT (H16) observatories. Lightcurve analysis gave a rotation periodof3.418±0.001 hours with a brightness amplitude of 0.11 magnitude (U=2).[12] A previous observation at the Palomar Transient Factory from August 2012, only gave a fragmentary lightcurve with a longer period of 7.935 hours (U=1).[16]
According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Hipparchus measures between 15.13 and 18.87 kilometers in diameter and its surface has a low albedo between 0.039 and 0.052.[7][8][9][10][11] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for a stony asteroid (rather than for a carbonaceous one) and consequently and calculates a smaller diameter of 8.18 kilometers based on an absolute magnitude of 12.8.[13]
^ abcdMainzer, A. K.; Bauer, J. M.; Cutri, R. M.; Grav, T.; Kramer, E. A.; Masiero, J. R.; et al. (June 2016). "NEOWISE Diameters and Albedos V1.0". NASA Planetary Data System: EAR-A-COMPIL-5-NEOWISEDIAM-V1.0. Bibcode:2016PDSS..247.....M. Retrieved 31 October 2018.
^ abcdUsui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. (online, AcuA catalog p. 153)
^ abOdden, Caroline E.; Bond, J. Brooke; Aggarwal, Ashok K.; Seokjun, Yoon; Chapman, Kathryn J.; Fortin, Liam G.; et al. (October 2014). "Lightcurve Analysis for Three Asteroids: 4000 Hipparchus, 5256 Farquhar and 5931 Zhvanetskij". The Minor Planet Bulletin. 41 (4): 274–275. Bibcode:2014MPBu...41..274O. ISSN1052-8091.