Sirene

Key Facts

• Categorized as a Mars-crossing Asteroid
• Comparable in size to the San Francisco Bay
• Not a Near Earth Object
• Not a Potentially Hazardous Object
• See orbit simulation

Overview

Sirene is a mid-sized 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 1,560 days (4.27 years), coming as close as 1.44 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 4.391 to 9.818 kilometers in diameter, making it larger than 99% of asteroids, very roughly comparable in size to the San Francisco Bay.

The rotation of Sirene has been observed. It completes a rotation on its axis every 2.88 hours.

No Close Approaches

Sirene's orbit is 0.45 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.

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 June 19, 2023. The IAU Minor Planet Center records 1,600 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:

• 23 Thalia (A852 XA)
• 53 Kalypso (A858 GA)
• 78 Diana (A863 EA)

References

• JPL Small Body Database
• Mission Design
• Sky Finder Chart

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.

Size Rendering

The above comparison is an artistic rendering that uses available data on the diameter of Sirene 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.