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Post by carlos on Mar 26, 2008 13:09:55 GMT
Looks like sunspot cycle 24 has finally begun.
It's been expected (overdue) for a few years now, but at last a sunspot has appeared that has a reverse polarity from previous ones. So sunspot activity should now increase over the next few years.
A big clue is always the location of a sunspot - lately, at the tail-end of the previous cycle (23) sunspots have invariably been pretty much around the equator of the Sun. But this first sunspot of Cycle 24 is at a much more Northerly lattitude. At the beginning of a sunspot cycle, the spots appear at lattitudes of around 30 to 40 degrees North or South of the equator. As the cycle progresses, they migrate over a period of years towards the equator, where they meet around the time of sunspot maximum, then gradually fade in number and regularity towards minimum. Spots appearing at 30 to 40 degrees North or South are a sure sign of the start of the new cycle, and the upcoming build back up towards maximum.
I also read recently, that sunspot lattitude is relative to the rotation speed of the star - The Sun's period of around 25 days at the poles, and 35 days at the equator, equate to spots only forming between about 40° N and 40° S Apparantly a slower spinning star would only get spots near the equator, and some faster spinning stars can have very large, almost permanent, spots on the poles.
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Post by glactus on Mar 29, 2008 5:06:34 GMT
A very interesting and informative insertion Carlos.
Evidently now scientists can tell whether a star has a slow or fast moving rotation period just by studying the location of sunspots over a given time.
Glactus
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