2011 ES4

Very small Apollo-class Asteroid

Near-Earth
Space Reference » Apollo-class Asteroids » 2011 ES4

Key Facts

  • Categorized as a Apollo-class Asteroid
  • Comparable in size to a school bus or smaller
  • Will pass within 21,281,621 km of Earth in 2019
  • Classified as a Near Earth Asteroid (NEA)
  • Not a Potentially Hazardous Object
  • See orbit simulation

Overview

2011 ES4 is a very small asteroid whose orbit crosses the orbit of Earth. NASA JPL has classified 2011 ES4 as a "Near Earth Asteroid" due to its orbit's proximity to Earth, but it is not considered potentially hazardous because computer simulations have not indicated any imminent likelihood of future collision.

2011 ES4 orbits the sun every 419 days (1.15 years), coming as close as 0.83 AU and reaching as far as 1.36 AU from the sun. Based on its brightness and the way it reflects light, 2011 ES4 is probably between 0.011 to 0.051 kilometers in diameter, making it a small to average asteroid, very roughly comparable in size to a school bus or smaller.

Close Approaches

2011 ES4's orbit is 0.00 AU from Earth's orbit at its closest point. This means that its orbit is very close to Earth's orbit.

2011 ES4 has 18 close approaches predicted in the coming decades:

Date Distance from Earth (km) Velocity (km/s)
March 4, 2019 21,281,621 11.933
Sept. 2, 2020 1,479,025 8.056
March 13, 2027 2,008,127 7.736
May 1, 2035 24,682,102 6.115
June 22, 2043 28,238,312 7.000
Aug. 24, 2051 12,831,748 5.376
March 7, 2058 19,213,185 11.500
Sept. 7, 2059 12,357,855 10.137
March 18, 2066 8,806,839 6.090
May 27, 2074 28,359,570 7.004
July 29, 2082 21,275,959 5.478
March 5, 2089 23,942,942 12.460
Sept. 6, 2090 9,381,665 9.561
March 28, 2097 15,823,723 4.925
June 20, 2105 28,288,822 7.018
Sept. 2, 2113 2,004,279 7.363
March 4, 2120 27,374,532 13.131
Sept. 3, 2121 404,920 7.918

Images and Observations

2011 ES4's orbit is determined by observations dating back to Feb. 23, 2011. It was last officially observed on Sept. 12, 2020. The IAU Minor Planet Center records 142 observations used to determine its orbit.

Accessibility and Exploration

2011 ES4 can be reached with a journey of 362 days. This trajectory would require a delta-v of 8.052 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 31,879 potential trajectories and launch windows to this asteroid.

See more at the NHATS Mission Trajectories table for 2011 ES4.

Similar Objects

These objects have orbits that share similar characteristics to the orbit of 2011 ES4:

References

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Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 1.096 AU
  • Eccentricity: 0.2433
  • Inclination: 3.37°
  • Longitude of Ascending Node: 339.82°
  • Argument of Periapsis: 274.75°
  • Mean Anomaly: 287.32°

Physical Characteristics

  • Diameter: ~0.031 km
  • Magnitude: 25.9

Derived Characteristics

  • Orbit Period: 419 days (1.15 years)
  • Avg. Orbit Speed: 28.46 km/s
  • Aphelion Distance: 1.36 AU
  • Perihelion Distance: 0.83 AU

Map Comparison

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Orbit Simulation

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Sky Map

The position of 2011 ES4 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.

Size Rendering

The below comparison is an artistic rendering that uses available data on the diameter of 2011 ES4 to create an approximate landscape rendering with New York City in the background. This approximation is built for full-resolution desktop browsers. Shape, color, and texture of asteroid are imagined.