Key Facts

  • Categorized as a Aten-class Asteroid
  • Comparable in size to a school bus or smaller
  • Will pass within 13,975,405 km of Earth in 2020
  • Classified as a Near Earth Asteroid (NEA)
  • Not a Potentially Hazardous Object
  • See orbit simulation

Overview

2009 SJ18 is a very small asteroid whose orbit could bring it in close proximity to Earth. NASA JPL has classified 2009 SJ18 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.

2009 SJ18 orbits the sun every 336 days (0.92 years), coming as close as 0.84 AU and reaching as far as 1.05 AU from the sun. Based on its brightness and the way it reflects light, 2009 SJ18 is probably between 0.021 to 0.094 kilometers in diameter, making it a small to average asteroid, very roughly comparable in size to a school bus or smaller.

Close Approaches

2009 SJ18's orbit is 0.05 AU from Earth's orbit at its closest point. This means that there is a wide berth between this asteroid and Earth at all times.

2009 SJ18 has 10 close approaches predicted in the coming decades:

Date Distance from Earth (km) Velocity (km/s)
Sept. 13, 2020 13,975,405 7.062
Feb. 24, 2021 25,534,237 8.023
March 24, 2032 23,236,779 8.219
April 19, 2043 27,015,985 7.948
Oct. 4, 2043 14,993,854 7.128
Sept. 24, 2054 6,832,502 6.645
Sept. 16, 2065 11,252,710 6.863
Sept. 2, 2076 28,885,790 8.708
Oct. 2, 2088 14,095,793 7.044
Sept. 23, 2099 6,746,204 6.641

Images and Observations

2009 SJ18's orbit is determined by observations dating back to Sept. 21, 2009. It was last officially observed on Sept. 30, 2009. The IAU Minor Planet Center records 24 observations used to determine its orbit.

Accessibility and Exploration

2009 SJ18 can be reached with a journey of 370 days. This trajectory would require a delta-v of 9.336 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 4,251 potential trajectories and launch windows to this asteroid.

See more at the NHATS Mission Trajectories table for 2009 SJ18.

Similar Objects

These objects have orbits that share similar characteristics to the orbit of 2009 SJ18:

References

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Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 0.9452 AU
  • Eccentricity: 0.1108
  • Inclination: 12.57°
  • Longitude of Ascending Node: 0.34°
  • Argument of Periapsis: 172.97°
  • Mean Anomaly: 265.99°

Physical Characteristics

  • Diameter: ~0.058 km
  • Magnitude: 24.6

Derived Characteristics

  • Orbit Period: 336 days (0.92 years)
  • Avg. Orbit Speed: 30.60 km/s
  • Aphelion Distance: 1.05 AU
  • Perihelion Distance: 0.84 AU

Map Comparison

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Orbit Simulation

Sky Map

The position of 2009 SJ18 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 2009 SJ18 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.