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Sormano Astronomical Observatory

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

(99942) Apophis, Greek name of Apep - the Egyptian god of evil and destruction, was discovered by R.A Tucker, D.J. Tholen and F. Bernardi on June 19, 2004 at Kitt Peak (code 695). Observed only two nights it was rediscovered on December 18, 2004 at Siding Spring Survey (code E12).

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 was just 14 degrees above the local horizon.

Herschel Space Observatory made the first thermal infrared observations of this asteroid returning a more precise diameter of 325 +/- 15 m.

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, if necessary, using a "gravitational tractor".

Results and diagrams of Apophis close encounter in 2029 and orbital path

The following results computed at Sormano Observatory on Dec. 2, 2014 using a software developed at Sormano and OrbFit 4.2 (OrbFit Software Package - Univ. of Pisa Italy), are based on 13 radar delay, 7 Doppler and 4182 optical observations from March 15, 2004 to February 26, 2014.

According to our computations, Apophis will pass at a nominal distance of 38315 Km (about 32000 Km from Earth's surface) on April 13, 2029 at 21h 45.1min UT, about 8 minutes before its passage at the MOID point. (see the below diagrams)

Date (UT) Nominal Distance (AU) Min possible distance (AU) Max possible distance (AU)
2029-04-13.906 0.00025612 0.00025607 0.00025617

For more details see our lists:

TECA - Table of Asteroids Next Closest Approaches to the Earth
TAM - Table of Asteroids Next Closest Approaches to the Moon
MBPL - Minor Body Priority List ( Asteroids with H < = 22.0 )

Diagram of the Minimum Orbital Intersection Distance (MOID ):


The diagrams below show Apophis's path in reference to the Earth - Moon system as follows:

Earth_Apophis Earth_Apophis_Moon Moon_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"

    NEODYS summary page:

  • NEODYS - (99942) Apophis

    See also:

  • (99942) Apophis from wikipedia
  • JPL orbit diagram
  • B612 Foundation
  • B612 Foundation - gravitational tractor
  • E.A.R.N. - DLR NEA database
  • Planetary Society competition prize
  • JPL Sentry System
  • NeoDys Risk page

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    Web Curators: F. Manca, M. Carpino
    Last modified: December 19, 2014