The first telescopes were developed at the beginning of the 17th century. Modern successors were given a mystery. From 1645 to 1715, the spots were all but gone. Gathering sunspot counts and other historical observations, astronomer John Eddy concluded that the Sun had taken a 70 year nap, which he called the Maunder Minimum after an astronomer couple who had previously studied it.
The Sun is not the only star that sleeps. By building a decades-long record of observations of a few dozen stars at specific wavelength that trace stellar activity, a team of astronomer has identified another star going through its own Maunder Minimum period The astronomer at the University of Hawaii, Manoa, who was not involved in the discovery, believes this is a Maunder Minimum star.
The finding, reported in a preprint last month on arXiv, may help explain what triggered the Sun's strange behavior 400 years ago. The way to study the future of the Sun is through this. The discovery supports a theory she and colleagues have advanced, that such events are an occasional symptom of a critical transition in the magnetic field of Sun-like stars. Astronomers theorize that the Sun's transition helped favor the emergence of life on Earth and that searching for stars in a similar stage could help identify other solar systems.
Scientists have known for a long time that the activity of our Sun varies from year to year. Sunspots are marked by weak points in the magnetic field during a solar maximum. Young Sun-like stars have similar cycles and older ones have stable activity. No one had seen a cyclist turn flat.
Anna Baum used 59 stars taken by the Mount Wilson Observatory and the W. M. Keck Observatory to create a 50-year chronology of star evolution. One star appeared to show a drastic shift during a 7 year gap in data. Over the course of 17 years, it went from cycling to being virtually flat.
Baum thought that the observatories were looking at two different stars. The data gap was filled by additional observations that captured the star's emissions as it switched from active to quiet. Jacob Luhn, an astronomer at the University of California, Irvine, is the lead author on the preprint.
There is a popular theory about why these periods occur. Stars spin more slowly because their solar winds act asmagnetic brakes, like a child sticking out their arms. A shift in the stars' magnetic field was noticed by van Saders and her colleague in 2016 The stabilizing of the spin rate was linked to a weakened magnetic field with the help of computer simulations. The Maunder Minimum can be caused by random changes in the star's magnetic field when it transitions to a flat state.
This transition state is predicted to emerge in middle-aged stars like our Sun and this newly identified napping star. The discovery has confirmed what we have been saying for the last five years. We were aware of stars that were not cycling, but we didn't know how they got there.
Life on Earth first crawled out of the sea, and that may be why the Sun's magnetic transition started around the same time. Particles and radiation from active stars cause damage to the human body. He says they may be part of the necessary ingredients. At some point, energetic space weather can pose a threat to complex life.
The ideal balance of protection and spark is provided by stars who are transitioning from cycling to stable. The best place to look for technological civilizations is around stars that are in the second half of their lives.
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