||OAS - Osservatorio Astronomico
Asteroid (99942) Apophis
Sormano Astronomical Observatory
Asteroid (99942) Apophis will approach the Earth on April 13, 2029.
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.
(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
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
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
or the inner planets
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 - (99942) Apophis
NEODYS summary page:
(99942) Apophis from wikipedia
JPL orbit diagram
B612 Foundation - gravitational tractor
NASA Ames Research center
Planetary Society competition prize
JPL Sentry System
NeoDys Risk page
Back to Sormano Astronomical Observatory Home Page
Web Curators: F. Manca, M. Carpino
Last modified: May 21, 2013