There are both acceleration and deceleration configurations every few years but for 11 years periods one dominates the other and the best aligned L-shapes are always around solar minima. I have only included the 1900s but I have checked the 1800s also showing the same.
Because the Sun is revolving around the barycenter it will have to decrease it's rotation when beeing accelerated and visa versa. We should perhaps be able to detect this variation, and we are:
Figure 3. The deviation of the rotation velocity from its average value at
corresponding latitudes. The "window" for the spectral analysis was 12 years.
The regions where rotation decelerates painted dark. The velocity was averaged
over the northern and southern hemispheres.
From: http://www.solarstation.ru/TL/PDF/tl_22.pdf
22-Year Variations of the Solar Rotation
A. G. Tlatov and V. I. Makarov
Kislovodsk solar station of the Pulkovo observatory, Kislovodsk, Russia
Pulkovo Astronomical Observatory, Saint Petersburg, Russia
Then we put in the periods of favourable configuration (from http://math-ed.com/Resources/GIS/Geometry_In_Space/java1/Temp/TLVisPOrbit.html)
Perhaps we should also be able to find traces of the planatary conjunctions in the Sun.
The following figures are from http://arxiv.org/PS_cache/arxiv/pdf/0711/0711.0799v1.pdf
Temporal Variations in the Sun’s Rotational Kinetic Energy
H. M. Antia, S. M. Chitre and D. O. Gough
Blue lines with conjunctions my addition
Thanks lgl. Why have you kept this quiet for so long? :)
ReplyDeleteHowever, the Ju-Ea synodic is not 1 yr but 1.092 and the Ju-Ve synodic is not 0.6yr but 0.649.
ReplyDeleteSo you seem to have the blue line for Ju-Ve in the right place (1/0.649=1.54) but the blue line fr Ju-Ea should be at 0.91, not 0.98.
ReplyDeleteAgree, I probably should not have included 0.98 but usually I'm happy with 90% accuracy.
Deletelgl,
ReplyDeleteThis article was not written in 2009. When did you updated the article to incorporate
the work of Tlatov and Makarov.
lgl,
ReplyDeleteIf you look carefully at the Earth's orbital velocity on January the 1st (after correcting for the change from the Julian to Gregorian calenders), you find that there is a 11.86 year oscillation of ~ 2 m /sec. If you assume that the Earth-Sun system acted like a rigid body pivoting about its centre-of-mass(~ 500 km from the centre of the Sun), and that Jupiter tugs on the Earth whenever it at right angles to the Earth-Sun line, then this translates into slow (0.7/150 * 2) ~ 0.0093 m/sec peak-to-peak change in the rotation rate of the Sun at its surface over an 11.86 year period. I may be wrong but I believe that this is far too small to make much difference.
Alternatively, if you look at the Sun's orbital motion about the centre-of-mass of the Solar System, you find that it looses and gains about 5 x 10^40 Nms of angular momentum as it moves through a 19.9 year orbital cycle. You would only have to transfer ~ 0.1 % of this orbital momentum into spin angular momentum of the Sun to produce changes in the rotation velocity of the Sun's convective layers of ~ 6 m/sec. I believe that this is a more likely scenario.