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OAS > Asteroid (99942) Apophis

Sormano Astronomical Observatory

Asteroid (99942) Apophis will approach the Earth on April 13, 2029.

(99942) Apophis, the Greek name of Apep - the Egyptian god of evil and destruction, was discovered by Tholen and Bernardi on June 19, 2004 at Kitt Peak (code 695) but observed over two nights then rediscovered on December 18, 2004 at Siding Spring Survey (code E12). Herschel Space Observatory made the first thermal infrared observations of this asteroid returning a more precise diameter of 325 15 m.

Here are available AVI(about 4 Mb) or GIF (about 1 Mb) animation of n.6 CCD images taken at Sormano (Italy) on December 30, 2004 when the object, crossing Cetus, was just 14 above the horizon.

According to our computations, that include also Arecibo radar astrometry, (99942) Apophis will pass at a minimum geocentric distance will be about 38400 Km (or 32000 km from Earth's surface) on April 13, 2029. For more details see our TECA and MBPL lists.

Using recent observations, NASA scientists reduce the likelihood of an hazardous encounter with our planet in 2036 but its follow up is still a priority. (see NASA ruled out Earth impact in 2036 for asteroid Apophis). Investigation to plan a spacecraft rendezvous with this asteroid is under consideration both to perform more accurate study on its chemical composition or to deflect it using a "gravitational tractor", if necessary.


Diagrams of close encounter and orbital path

All the diagrams were extrapolated from internal software used also to compute close encounters between asteroids and the Earth ( SAEL, MBPL and TECA) or the inner planets

(99942) Apophis


See the BBC Online article (March 25, 2010) "Cuts cast doubt on asteroid plan"

For more information please see JPL reference:

  • Predicting Apophis' Earth Encounters in 2029 and 2036
  • Publication "Predicting the Earth encounters of (99942) Apophis"
    by Jon D. Giorgini, Lance A.M. Benner, Steven J. Ostro, Michael C. Nolan b, Michael W. Busch
  • NASA refines asteroid Apophis'path toward Earth
  • JPL' animation "Apophis unknown_bias"

    or
    NEODYS summary page:

  • NEODYS - (99942) Apophis

    See also:

  • (99942) Apophis from wikipedia
  • JPL orbit diagram
  • B612 Foundation
  • B612 Foundation - gravitational tractor
  • NASA Ames Research center
  • Planetary Society competition prize
  • JPL Sentry System
  • NeoDys Risk page


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    Web Curators: F. Manca, M. Carpino
    Last modified: May 21, 2013