1 November 1978 (). Physical characteristics Adonis has an absolute magnitude of 18.8, and an estimated mean-diameter between 520 and 600 meters. As of 2017, the body's rotation period, composition, spectral type and shape remain unknown. Exploration A famous Tintin book shows this asteroid too near from the Earth but Adonis was considered as a possible target for a 6 million km distant flyby by the Vega 2 spacecraft after its 1986 flyby of Halley's Comet. In the event Vega 2 didn't have enough fuel post Halley encounter to make the necessary orbital changes for the flyby. References External links Long-lost planet 1936 CA ("Adonis") recovered Benner, et al. - Radar Detection of Near-Earth Asteroids 2062 Aten, 2101 Adonis, 3103 Eger, 4544 Xanthus, and 1992 QN (1997) Asteroid Lightcurve Database (LCDB), query form (info ) Dictionary of Minor Planet Names, Google books Discovery Circumstances: Numbered Minor Planets (1)–(5000) Minor Planet Center 002101 Discoveries by Eugène Joseph Delporte Named minor planets 002101 002101 19360212