99942 Apophis

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99942 Apophis
Animation o 99942 Apophis frae the Osservatorio Astronomico Sormano
Discovery[1]
Discovered bi Roy A. Tucker
David J. Tholen
Fabrizio Bernardi
Discovery steid Kitt Peak[1]
Discovery date 19 June 2004
Designations
Named after
Apep
2004 MN4
Aten Aten
NEO, PHA[1]
Orbital chairactereestics[1]
Epoch 7 December 2007 (JD 2454441.5)
Uncertainty parameter 0
Observation arc 3635 days (9.95 yr)
Aphelion 1.09851 AU (164.335 Gm)
Perihelion 0.74605 AU (111.607 Gm)
0.92228 AU (137.971 Gm)
Eccentricity 0.19108
0.89 yr (323.5 d)
30.728 km/s
215.53998°
1.11278°/day
Inclination 3.33129°
204.45719°
126.39364°
Yird MOID 0.000659446 AU (98,651.7 km)
Jupiter MOID 4.12656 AU (617.325 Gm)
Jupiter Tisserand parameter 6.467
Pheesical chairactereestics
Dimensions 325±15 m[2]
Mean radius
0.1625 ± 0.0075 km
Mass 4×1010 kg (assumed)[3]
Mean density
~3.2 g/cm3[4]
Equatorial surface gravity
0.00027 m/s2 (average)
Equatorial escape velocity
~0.52 km/h[5]
30.4 h (1.27 d)[1][6]
tumbling:[7]
precession period:
27.38±0.07 h[7]
rotation period:
263±6 h[7]
period of harmonic with strongest lightcurve amplitude:
30.56±0.01 h[7]
0.23[2]
Temperatur 270 K
Sq [6]
19.7 ± 0.4[1][6]

99942 Apophis (previously kent bi its provisional designation 2004 MN4) is a near-Yird asteroid that caused a brief period o concern in December 2004 acause ineetial observations indicatit a probability o up tae 2.7% that it wad hit Yird on Aprile 13, 2029. Addeetional observations providit improved predictions that eliminatit the possibility o an impact on Yird or the Muin in 2029.

References[eedit | eedit soorce]

  1. 1.0 1.1 1.2 1.3 1.4 1.5 "JPL Small-Body Database Browser: 99942 Apophis (2004 MN4)" (last observation: 2014-02-26; arc: 9.95 years). Retrieved 12 April 2016. 
  2. 2.0 2.1 ESA (January 9, 2013). "Herschel intercepts asteroid Apophis". European Space Agency (ESA). Retrieved 2013-01-09. 
  3. "99942 Apophis (2004 MN4) Earth Impact Risk Summary". NASA. Archived frae the oreeginal on 2013-05-11. Retrieved 2015-03-03. 
  4. Binzel, Richard P. (2007). "Can NEAs be Grouped by Their Common Physical Characteristics?" (PDF). Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology. aero.org. Archived frae the oreeginal (PDF) on 2012-04-12. 
  5. assuming radius of 0.135 km and mass of 2.1e10 kg yields an escape velocity of 0.14 m/s or 0.52 km/h.
  6. 6.0 6.1 6.2 "99942 Apophis". The Near-Earth Asteroids Data Base at E.A.R.N. Retrieved 2009-10-15. 
  7. 7.0 7.1 7.2 7.3 Pravec, P.; Scheirich, P.; Ďurech, J.; Pollock, J.; Kušnirák, P.; Hornoch, K.; Galád, A.; Vokrouhlický, D.; Harris, A.W.; Jehin, E.; Manfroid, J.; Opitom, C.; Gillon, M.; Colas, F.; Oey, J.; Vraštil, J.; Reichart, D.; Ivarsen, K.; Haislip, J.; LaCluyze, A. (2014). "The tumbling spin state of (99942) Apophis" (PDF). Icarus. 233: 48–60. Bibcode:2014Icar..233...48P. doi:10.1016/j.icarus.2014.01.026.