101554 (1999 AL4)

Mid-sized Mars-crossing Asteroid

Space Reference » Mars-crossing Asteroids » 101554 (1999 AL4)

Key Facts

Overview

101554 (1999 AL4) is a mid-sized asteroid with an orbit that crosses the orbit of Mars. NASA JPL has not classified 1999 AL4 as potentially hazardous because its orbit does not bring it close to Earth.

1999 AL4 orbits the sun every 1,310 days (3.59 years), coming as close as 1.56 AU and reaching as far as 3.13 AU from the sun. Based on its brightness and the way it reflects light, 1999 AL4 is probably between 1.646 to 3.682 kilometers in diameter, making it larger than 99% of asteroids, very roughly comparable in size to Mount Everest.

No Close Approaches

1999 AL4's orbit is 0.73 AU from Earth's orbit at its closest point. This means that there is a very wide berth between this asteroid and Earth at all times.

Orbital simulations conducted by NASA JPL's CNEOS do not show any close approaches to Earth.

Images and Observations

1999 AL4's orbit is determined by observations dating back to Sept. 16, 1987. It was last officially observed on June 23, 2023. The IAU Minor Planet Center records 585 observations used to determine its orbit.

Accessibility and Exploration

This asteroid is not considered a viable target for human exploration by the NHATS study.

Similar Objects

These objects have orbits that share similar characteristics to the orbit of 1999 AL4:

References

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Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 2.346 AU
  • Eccentricity: 0.3337
  • Inclination: 21.87°
  • Longitude of Ascending Node: 310.13°
  • Argument of Periapsis: 86.17°
  • Mean Anomaly: 329.82°

Physical Characteristics

  • Diameter: ~2.126 km
  • Magnitude: 16.04

Derived Characteristics

  • Orbit Period: 1,310 days (3.59 years)
  • Avg. Orbit Speed: 19.48 km/s
  • Aphelion Distance: 3.13 AU
  • Perihelion Distance: 1.56 AU

Map Comparison

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Orbit Simulation

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Sky Map

The position of 101554 (1999 AL4) 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 above comparison is an artistic rendering that uses available data on the diameter of 1999 AL4 to create an approximate landscape rendering with Mount Everest in the background. This approximation is built for full-resolution desktop browsers. Shape, color, and texture of asteroid are imagined.