Key Facts

  • Categorized as a Apollo-class Asteroid
  • Comparable in size to the San Francisco Bay (6.25 km diameter)
  • Will pass within 12,353,353 km of Earth in 2050
  • Classified as a Near Earth Asteroid (NEA)
  • Classified as a Potentially Hazardous Asteroid (PHA)
  • See orbit simulation


Phaethon is a mid-sized asteroid whose orbit crosses the orbit of Earth. NASA JPL has classified Phaethon as a "Potentially Hazardous Asteroid" due to its predicted close pass(es) with Earth.

Phaethon orbits the sun every 524 days (1.43 years), coming as close as 0.14 AU and reaching as far as 2.40 AU from the sun. Its orbit is highly elliptical. Phaethon is about 6.3 kilometers in diameter, making it larger than 99% of asteroids, comparable in size to the San Francisco Bay.

The rotation of Phaethon has been observed. It completes a rotation on its axis every 3.60 hours.

Phaethon's spectral type F (Tholen) / B (SMASSII) indicates that it is likely to contain hydrogen, nitrogen, ammonia, and iron.

Close Approaches

Phaethon's orbit is 0.02 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.

Phaethon has 9 close approaches predicted in the coming decades:

Date Distance from Earth (km) Velocity (km/s)
Dec. 11, 2050 12,353,353 36.236
Dec. 18, 2060 16,623,819 30.648
Dec. 14, 2093 2,965,809 34.235
Dec. 22, 2103 25,661,125 29.015
Dec. 13, 2136 8,237,421 35.401
Dec. 19, 2146 13,502,132 31.170
Dec. 9, 2179 28,507,620 39.646
Dec. 15, 2189 5,308,473 34.795
Dec. 20, 2199 14,196,085 31.016

Images and Observations

Phaethon's orbit is determined by observations dating back to Oct. 27, 1983. It was last officially observed on Oct. 26, 2022. The IAU Minor Planet Center records 5,620 observations used to determine its orbit.

Scientists have been able to determine this object's shape:

View asteroid Phaethon in 3D.

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 Phaethon:



   or view a random object

Orbital Elements

  • Epoch: 2460200.5 JD
  • Semi-major axis: 1.271 AU
  • Eccentricity: 0.89
  • Inclination: 22.29°
  • Longitude of Ascending Node: 265.15°
  • Argument of Periapsis: 322.24°
  • Mean Anomaly: 334.02°

Physical Characteristics

  • Diameter: 6.25000 km
  • Magnitude: 14.4
  • Albedo: 0.1066
  • Spectral type (Tholen): F
  • Spectral type (SMASS): B

Derived Characteristics

  • Orbit Period: 524 days (1.43 years)
  • Avg. Orbit Speed: 26.39 km/s
  • Aphelion Distance: 2.40 AU
  • Perihelion Distance: 0.14 AU
  • Rotation Period: 3.60 hours
  • Approx. Composition: hydrogen, nitrogen, ammonia, and iron.

Map Comparison

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Orbit Simulation

Sky Map

The position of Phaethon 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 Phaethon 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.