Polar and Low-Latitude Faculae in Activity Cycles 23–24

Abstract

Polar and low-latitude faculae were identified in daily images based on white-light observations from the MDI (1996–2011) and SOHO (2010–2019) space observatories. The boundaries of the faculae were combined with magnetic field observations at the closest possible instant of observation. The time and latitude distributions, as well as other properties of polar and low-latitude faculae, were analyzed. The resulting data on polar faculae were supplemented with observational data from Mitaka Observatory (Japan) for the period of 1951–1999. Thus, we compiled a summary series of polar activity for the period of 1951–2019. The distributions of polar faculae by area and magnetic field intensity are considered. The maximum distribution of the facula area at latitudes above θ > 55° occurs at values of approximately 6–10 mhs. The magnetic field of polar faculae has a maximum of B ~ 70–100 G. The amplitude of polar activity at the minimum in the 25th cycle approximately matches the amplitude in the 24th cycle. It can be expected that the amplitude of the sunspot activity cycle will be close to that of cycle 24.