Magnetic activity cycles in the chromospherically active secondary component induce changes in its radius of gyration that have been linked to recurrent orbital period variations on the order of H " 10 " 5 via the Applegate mechanism.
32.
They say the results lend tenuous support to a highly controversial theory that the earth is cloudier, and therefore reflects more sunlight, when the sun is near the minimum of its 11-year activity cycle and has the fewest sunspots and solar storms.
33.
The non-existence of Gliese 581 f was accepted relatively quickly : it was shown that the radial velocity variations that led to the claimed discovery of Gliese 581 f were instead associated with the stellar activity cycle rather than an orbiting planet.
34.
Observations of short term variations in the chromatic activity suggest that the star undergoes differential rotation, with a rotation period of about 11 13 days . Its surface has a measured activity cycle of 16.6 years, compared to 11 years on the Sun.
35.
The "'solar cycle "'or "'solar magnetic activity cycle "'is the nearly periodic 11-year change in the Sun's activity ( including changes in the levels of solar radiation and ejection of solar material ) and appearance ( changes in the number and size of sunspots, flares, and other manifestations ).
36.
The orbit of the stars in the binary pair is gravitationally coupled to their shape changes, so that the period shows modulations ( typically on the order of " P / P < " 10 " 5 ) on the same time scale as the activity cycles ( typically on the order of decades ).
