Key Facts

Overview

Sirene is a small asteroid with an orbit that crosses the orbit of Mars. NASA JPL has not classified Sirene as potentially hazardous because its orbit does not bring it close to Earth.

Sirene orbits the sun every 1,554 days (4.25 years), coming as close as 1.43 AU and reaching as far as 3.82 AU from the sun. Based on its brightness and the way it reflects light, Sirene is probably between 4.411 to 9.864 kilometers in diameter, making it larger than most asteroids, very roughly comparable in size to the San Francisco Bay.

No Close Approaches

Sirene's orbit is 0.44 AU from Earth's orbit at its closest point. This means that there is an 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

Sirene's orbit is determined by observations dating back to Oct. 31, 1923. It was last officially observed on Aug. 18, 2019. The IAU Minor Planet Center records 852 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 Sirene:

References

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Orbital Elements

  • Epoch: 2458600.5 JD
  • Semi-major axis: 2.62517511742 AU
  • Eccentricity: 0.455499830078
  • Inclination: 15.7696757021°
  • Longitude of Ascending Node: 229.461495415°
  • Argument of Periapsis: 186.428746581°
  • Mean Anomaly: 150.612209173°

Physical Characteristics

  • Diameter: ~5.695 km
  • Magnitude: 13.9

Derived Characteristics

  • Orbit Period: 1,554 days (4.25 years)
  • Avg. Orbit Speed: 18.38 km/s
  • Aphelion Distance: 3.82 AU
  • Perihelion Distance: 1.43 AU

Size Comparison

Orbit Simulation

Sky Map

The position of Sirene 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.