Comet Encounters and Carbon 14

Abstract

The ${}^{14}$C production of shock-accelerated particles is calculated in terms of the total energy released in energetic particles. The recently reported 1.2% jump in the ${}^{14}$C content of the atmosphere in the year C.E. 775, it is found, would require $\gtrsim 10^{34}$ erg in energetic particles, less than first estimates but far more than any known solar flare on record. It is noted that the superflare from a large comet (comparable to C/Hale-Bopp) colliding with the sun could produce shock-accelerated GeV cosmic rays in the solar corona and/or solar wind, and possibly account for the CE 775 event. Several additional predictions of cometary encounters with the sun and other stars may be observable in the future.

to appear in ApJ Letters

References in corpus (2)

• A new model of cosmogenic production of radiocarbon 14C in the atmosphere
• Comet C/2011 W3 (Lovejoy): Orbit Determination, Outbursts, Disintegration of Nucleus, Dust-Tail Morphology, and Relationship to New Cluster of Bright Sungrazers

Cited by in corpus (10)

• The AD775 cosmic event revisited: the Sun is to blame
• Extreme solar events
• AD 775 Pulse of Cosmogenic Radionuclides Production as Imprint of a Galactic Gamma-Ray Burst
• Terrestrial effects of possible astrophysical sources of an AD 774-775 increase in 14C production
• Supernovae and Single-Year Anomalies in the Atmospheric Radiocarbon Record
• Records of sunspot and aurora activity during 581-959 CE in Chinese official histories in the periods of Suí, Táng, and the Five Dynasties and Ten Kingdoms
• A comet could not produce the carbon-14 spike in the 8th century
• A solar super-flare as cause for the 14C variation in AD 774/5 ?
• Destruction and Observational Signatures of Sun-Impacting Comets
• The Chinese comet observation in AD 773 January