Year: 2023
Type: article
Abstract: Characterizing the cyclic magnetic activity of stars that are close approximations of our Sun offers our best hope for understanding our Sun’s current and past magnetism, the space weather around solar-type stars, and more generally, the dynamos of other cool stars. The nearest current approximation to the Sun is the solar twin 18 Scorpii, a naked-eye Sun-like star of spectral type G2 Va. However, while 18 Scorpii’s physical parameters closely match those of the Sun, its activity cycle is about 7 yr, and shorter than the solar cycle. We report the measurement of a periodicity of 15 yr that corresponds to a longer activity cycle for 18 Scorpii based on observations extending to the last three decades. The global magnetic geometry of 18 Scorpii changes with this 15 yr cycle and appears to be equivalent to the solar 22 yr magnetic polarity cycle. These results suggest that 18 Scorpii is also a magnetic proxy for a younger Sun, adding an important new datum for testing dynamo theory and magnetic evolution of low-mass stars. The results perturb our understanding of the relationship between cycle and rotation, constrain the Sun’s magnetism and the Sun–Earth connection over the past billion years, and suggest that solar Schwabe and Hale cycle periods have increased over that time span.
Source: The Astrophysical Journal
Institutions: Universidade Federal do Rio Grande do Norte, Center for Astrophysics Harvard & Smithsonian, Leibniz Institute for Astrophysics Potsdam, Universidade Federal do Rio de Janeiro, Valongo Observatory, Lowell Observatory, Laboratório Nacional de Astrofísica, Centre National de la Recherche Scientifique, Institut de Recherche en Astrophysique et Planétologie, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Université Paris-Saclay, Astrophysique, Instrumentation et Modélisation, CEA Paris-Saclay, Institut de Recherche sur les Lois Fondamentales de l'Univers
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Awards: G1756730146, G2365298233, G385647981, DATA FROM OTHER STARS CAN HELP SOLAR DYNAMO MODELS, PUTTING MORE ON CONSTRAINTS ON THE MODELS, AND THEN TESTING THEM OVER A WIDE RANGE OF PROPERTIES., G5216973458, The Whole Sun Project: Untangling the complex physical mechanisms behind our eruptive star and its twins, G7752285598, G8732841285
OpenAlex ID: W4388639730