On the Presence of Two Populations of Sunspots
Abstract
Using historical (1894-1976) and more modern (1977-2014) observations, we investigate statistical properties of distributions of sunspot areas and their long-term variations. We confirm the presence of two populations of sunspots with smaller and larger areas, and show that sunspot/group lifetime can be used to separate the two populations on small short-lived sunspot groups (SSG) and large long-lived groups (LLG). The area properties of LLG are nearly constant over the entire period of observations, while the SSGs show significant long-term variations. Based on the presence of long-term variations in one component and the absence of those in the other, we suggest that the production of two populations of sunspots (SSG and LLG) may be affected by different processes.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2016
- DOI:
- 10.3847/1538-4357/833/1/94
- Bibcode:
- 2016ApJ...833...94N
- Keywords:
-
- Sun: activity;
- sunspots