Key Facts

  • Classified as a Aten-class Asteroid
  • Comparable in size to a football field (0.33 km diameter)
  • Will pass within 16,852,610 km of Earth in 2021
  • Classified as a Near Earth Asteroid (NEA)
  • Classified as a Potentially Hazardous Asteroid (PHA)
  • See orbit simulation

Overview

Apophis is a very small asteroid whose orbit could bring it in close proximity to Earth. NASA JPL has classified Apophis as a "Potentially Hazardous Asteroid" due to its predicted close pass(es) with Earth.

Apophis orbits the sun every 324 days (0.89 years), coming as close as 0.75 AU and reaching as far as 1.10 AU from the sun. Apophis is about 0.3 kilometers in diameter, making it a small to average asteroid, comparable in size to a football field.

The rotation of Apophis has been observed. It completes a rotation on its axis every 30.40 days.

Apophis's spectral type (Tholen) / Sq (SMASSII) indicates that it is likely to contain magnesium silicate and iron silicate.

Close Approaches

Apophis's orbit is 0.00 AU from Earth's orbit at its closest point. This means that its orbit is relatively close to Earth's orbit.

Apophis has 6 close approaches predicted in the coming decades:

Date Distance from Earth (km) Velocity (km/s)
March 6, 2021 16,852,610 4.585
April 13, 2029 37,725 7.433
May 26, 2058 16,109,793 4.577
April 2, 2094 28,783,471 11.523
Sept. 16, 2102 7,407,757 7.149
April 7, 2123 16,691,765 9.128

NASA Sentry has assessed impact risk for 12 very close approach scenarios. Here are the top scenarios ordered by probability of impact:

Date Distance from Earth (km) Distance Error (km) Probability of Impact (%) Impact Energy (Mt)
April 12, 2068 109.14 ±0.00 0.00067 1151.0
April 14, 2103 3,852.00 ±0.00 0.00005 1151.0
April 13, 2076 699.78 ±0.00 0.00005 1151.0
April 11, 2065 1,078.56 ±0.00 0.00003 1151.0
April 13, 2091 5,341.44 ±0.00 0.00002 1153.0
April 13, 2078 404.46 ±0.00 0.00002 1151.0
April 13, 2077 2,542.32 ±0.00 0.00002 1152.0
April 12, 2060 4,108.80 ±0.00 0.00001 1152.0
April 13, 2105 5,912.82 ±0.00 0.00001 1151.0
Oct. 15, 2089 1,117.08 ±0.00 0.00000 1153.0
Oct. 16, 2105 892.38 ±0.00 0.00000 1151.0
Oct. 15, 2068 3,242.10 ±0.00 0.00000 1151.0

Images and Observations

Apophis's orbit is determined by observations dating back to March 15, 2004. It was last officially observed on Jan. 3, 2015. The IAU Minor Planet Center records 4,481 observations used to determine its orbit.

Accessibility and Exploration

Apophis can be reached with a journey of 354 days. This trajectory would require a delta-v of 6.14 km/s. To put this into perspective, the delta-v to launch a rocket to Low-Earth Orbit is 9.7 km/s. There are 209,219 potential trajectories and launch windows to this asteroid.

See more at the NHATS Mission Trajectories table for Apophis.

Similar Objects

These objects have orbits that share similar characteristics to the orbit of Apophis:

References

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Orbital Elements

  • Epoch: 2454733.5 JD
  • Semi-major axis: 0.922438301908 AU
  • Eccentricity: 0.191195304831
  • Inclination: 3.33136952001°
  • Longitude of Ascending Node: 204.446028919°
  • Argument of Periapsis: 126.401879525°
  • Mean Anomaly: 180.429373046°

Physical Characteristics

  • Diameter: 0.32500 km
  • Magnitude: 19.7
  • Albedo: 0.23
  • Spectral type (SMASS): Sq

Derived Characteristics

  • Orbit Period: 324 days (0.89 years)
  • Avg. Orbit Speed: 31.01 km/s
  • Aphelion Distance: 1.10 AU
  • Perihelion Distance: 0.75 AU
  • Rotation Period: 30.40 days
  • Approx. Composition: magnesium silicate and iron silicate.

Size Comparison

Orbit Simulation

Sky Map

The position of Apophis is indicated by a ◯ pink circle. Note that the object may not be in your current field of view. Use the controls below to adjust position, location, and time.