Icarus orbits the Sun at a distance of 0.19–1.97 AU once every 13 months (409 days; semi-major axis of 1.08 AU). Its orbit has an eccentricity of 0.83 and an inclination of 23° with respect to the ecliptic.[4] The body's observation arc begins with its official discovery observation at Palomar in 1949.[1]
Icarus is thought to be the source of the Arietids,[21] a strong daylight meteor shower. However other objects such as the short-period Sun-grazing comet 96P/Machholz are also possible candidates for the shower's origin.[22]
The last close approach was on 16 June 2015, when Icarus passed Earth at 0.05383 AU (8,053,000 km; 20.95 LD).[6][23] Before that, the previous close approach was on 11 June 1996, at 0.10119 AU (15,138,000 km), almost 40 times as far as the Moon. The next notably close approach will be on 13 June 2043, at 0.0586 AU (8,770,000 km) from Earth.[23]
Naming
This minor planet was named after Icarus, son of Daedalus(also see 1864 Daedalus) from Greek mythology. They attempted to escape prison by means of wings constructed from feathers and wax. Icarus ignored his father's instructions not to fly too close to the Sun. When the wax in his wings melted he fell into the sea and drowned.[3] The naming was suggested by R. C. Cameron and Dr. Folkman. The official naming citation was published by the Minor Planet Center in January 1950 (M.P.C. 347).[26] Both mythological figures are honored with the lunar craters Icarus and Daedalus.[3]
Since 1968, several rotational lightcurves of Icarus were obtained from photometric and radiometric observations.[10][13][14] During the asteroid's close approach in June 2017, observations of the fast-moving object were taken by Italian astronomers Virginio Oldani and Federico Manzini, Brian Warner at the Palmer Divide Station (U82) in California, and by Australian astronomers at the Darling Range and Blue Mountains Observatories (Q68).[11][12][15][b]
According to several radiometric, photometric, and radar observations, including the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Icarus measures between 1.0 and 1.44 kilometers in diameter and its surface has an albedo between 0.14 and 0.51.[7][8][9][6][16][a]
Analysis of the radar data obtained at the Arecibo and Goldstone observatories in June 2015 gives the body's dimensions: 1.61 × 1.60 × 1.17 kilometers, with equivalent diameter of 1.44 kilometers.[6] The Collaborative Asteroid Lightcurve Link adopts an albedo of 0.14 based on the radar-derived equivalent diameter of 1.44 kilometers and absolute magnitude of 16.96.[18]
"Project Icarus" was a student project conducted at the Massachusetts Institute of Technology (MIT) in the spring of 1967 as a contingency plan in case of an impending collision with 1566 Icarus.
This project was an assignment by Paul Sandorff for his group of MIT systems engineering graduate students to devise a plan to use rockets to deflect or destroy Icarus in the case that it was found to be on a collision course with planet Earth.[29][30][31]Time magazine ran an article on the endeavor in June 1967[30] and the following year the student report was published as a book.[29][31][32]
The students' plan relied on the new Saturn V rocket, which did not make its first flight until after the report had been completed. During the course of their study, the students visited the Kennedy Space Center, Florida, where they were so impressed with the Vehicle Assembly Building that they wrote of "the awesome reality" that had "completely erased" their doubts over using the technology associated with the Apollo program and Saturn rockets.
The final plan hypothesized that six Saturn V rockets (appropriated from the then-current Apollo program) would be used, each launched at variable intervals from months to hours away from impact. Each rocket was to be fitted with a single 100-megaton nuclear warhead as well as a modified Apollo Service Module and uncrewed Apollo Command Module for guidance to the target. The warheads would be detonated 30 meters from the surface, deflecting or partially destroying the asteroid. Depending on the subsequent impacts on the course or the destruction of the asteroid, later missions would be modified or cancelled as needed. The "last-ditch" launch of the sixth rocket would be 18 hours prior to impact.[33]
In fiction
The report later served as the basis and inspiration for the 1979 science fiction film Meteor.[31][34]
^ abcMainzer, A.; Grav, T.; Masiero, J.; Bauer, J.; Cutri, R. M.; McMillan, R. S.; et al. (November 2012). "Physical Parameters of Asteroids Estimated from the WISE 3-Band Data and NEOWISE Post-Cryogenic Survey". The Astrophysical Journal Letters. 760 (1): 6. arXiv:1210.0502. Bibcode:2012ApJ...760L..12M. doi:10.1088/2041-8205/760/1/L12. S2CID41459166.
^ abGehrels, T.; Roemer, E.; Taylor, R. C.; Zellner, B. H. (March 1970). "Minor planets and related objects. IV. Asteroid (1566) Icarus". Astronomical Journal. 75: 186–195. Bibcode:1970AJ.....75..186G. doi:10.1086/110962.
^ abOey, Julian; Williams, Hasen; Groom, Roger (July 2017). "Lightcurve Analysis of Asteroids from BMO and DRO in 2015". The Minor Planet Bulletin. 44 (3): 200–204. Bibcode:2017MPBu...44..200O. ISSN1052-8091.
^ abMahapatra, Pravas R.; Ostro, Steven J.; Benner, Lance A. m.; Rosema, Keith D.; Jurgens, Raymond F.; Winkler, Ron; et al. (August 1999). "Recent radar observations of asteroid 1566 Icarus". Planetary and Space Science. 47 (8–9): 987–995. Bibcode:1999P&SS...47..987M. doi:10.1016/S0032-0633(99)00015-X.
^Ohtsuka, Katsuhito; Nakano, Syuichi; Yoshikawa, Makoto (2003), "On the Association among Periodic Comet 96P/Machholz, Arietids, the Marsden Comet Group, and the Kracht Comet Group", Publications of the Astronomical Society of Japan, 55: 321–324, doi:10.1093/pasj/55.1.321
^Project IcarusArchived 17 October 2007 at the Wayback Machine, MIT Report No. 13, MIT Press 1968, edited by Louis A. Kleiman. "Interdepartmental Student Project in Systems Engineering at the Massachusetts Institute of Technology, Spring Term, 1967"; reissued 1979.