The trajectory, structure and origin of the Chelyabinsk asteroidal impactor

Area of Science:

• Planetary Science
• Astronomy
• Geophysics

Background:

• Earth faces continuous impacts from asteroids and comets.
• Historical airburst events include Tunguska (1908), Indonesia (2009), and Marshall Islands (1994).
• The Chelyabinsk superbolide event on February 15, 2013, released an energy of 500 kilotons of trinitrotoluene.

Purpose of the Study:

• Analyze video records of the Chelyabinsk superbolide.
• Determine the atmospheric passage and origin of the Chelyabinsk object.
• Assess the asteroid's bulk strength and fragmentation behavior.

Main Methods:

• Analysis of selected video records of the Chelyabinsk superbolide.
• Orbital trajectory comparison with known asteroids.
• Estimation of bulk strength based on atmospheric fragmentation.

Main Results:

• The Chelyabinsk object's orbit is statistically similar to asteroid 86039 (1999 NC43), suggesting a shared origin.
• The asteroid's bulk strength was approximately one megapascal, indicating a heavily fractured stone.
• Fragmentation occurred between 45 and 30 km altitude, mitigating ground damage.
• The mass of surviving fragments over 100 grams was lower than anticipated.

Conclusions:

• The Chelyabinsk superbolide and asteroid 86039 likely originated from the same parent body.
• The asteroid's low bulk strength played a crucial role in its atmospheric breakup.
• Early atmospheric fragmentation significantly reduced the potential for widespread ground devastation.