Erratum to: The Maunder Minimum and the Sun as the Possible Source of Particles Creating Increased Abundance of the 14C Carbon Isotope

Abstract

The Maunder Minimum was the time during the second part of the 17th century, nominally from 1645 to 1717 AD, when unusually low numbers of sunspots were observed. On the basis of numerous recorded observations of auroras in the early 18th century, the end of the Minimum could be regarded as around 1700, but details of sunspot observations by Jan Heweliusz (Heweliusz, Machina Coelestis, 1679), John Flamsteed and Philippe de La Hire in 1684 allow us to interpret the Maunder Minimum as the period without a significant cessation of activity. This Minimum was also recognized in 14C data from trees which grew during the second part of 17th century. The variation in the production rate of radioactive carbon isotope 14C is due to modulation of the cosmic ray flux producing it by the changing level of solar activity and solar magnetic flux. Stronger magnetic fields in the solar wind make it more difficult for cosmic rays to reach the Earth, causing a drop in the production rate of 14C. However, more detailed analyses of 14C data indicate that the highest isotope abundances do not occur at the time of sunspot minima, as would be expected on the basis of modulation of the cosmic ray flux by the solar magnetic field, but two years after the sunspot number maximum. This time difference (or phase delay) can be accounted for if in fact there are both solar and non-solar cosmic ray contributions. Solar flares could also contribute high-energy particles and produce 14C and are generally not most frequent at the time of the highest sunspot numbers in the cycle. Solar flares, most frequent about two years after the sunspot maximum, could be the main source of increased 14C isotope abundance. This idea changes established earlier relations between sunspot number of this time regarded as low and increased abundance of 14C isotope, and allows us to interpret the Maunder Minimum as a botanical or statistical effect.