Abstract
According to standard solar models, the energy radiated from the surface of the Sun is equal to that generated by purely nuclear processes in the core. In the absence of perturbations, structural changes take place only on the nuclear evolutionary time scale; for example, during the last 108 yr, the Sun's semi-diameter would be expected to have increased by ∼4 arc s (ref. 1). Claims based on meridian transit measurements that the Sun has been shrinking on a much shorter time scale2, ∼1 arc s per century−1, and thereby changing its potential energy, have been disputed and upper limits on any secular decrease have been shown to be consistent with a constant diameter3,4. Measurements made during the 31 July 1981 total eclipse, reported here, together with a re-analysis of previous eclipse and Mercury transit measurements, confirm that there is no evidence for any secular change in the solar diameter, with a reduced upper limit. However, there is increased support for an ∼80-yr cyclic variation.
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References
Iben, I. Astrophys. J. 147, 624–663 (1967).
Eddy, J. A. & Boornazian, A. A. Bull. Am. astr. Soc. 11, 437 (1979).
Shapiro, I. I. Science 208, 51–53 (1980).
Parkinson, J. H., Morrison, L. V. & Stephenson, F. R. Nature 288, 548–551 (1980).
Parkinson, J. H. Q. J. R. astr. Soc. 23, 252–255 (1982).
Duncombe, J. S. U. S. Naval Observ. Circ. No. 141 (1973).
Jones, J. E. J. Br. astr. Ass. 91, 363–367 (1981).
Gilliland, R. L. Astrophys. J. 248, 1144–1155 (1981).
Dunham, D. W., Dunham, J. B., Fiala, A. D. & Sofia, S. in Variations of the Solar Constant (ed. Sofia, S.) 117–121 (NASA CP-2191, Washington, 1981).
Hoyt, D. V. Rev. Geophys. Space Phys. 17, 427–458 (1979).
Sofia, S., O'Keefe, J., Lesh, J. R. & Endal, A. S. Science 204, 1306–1308 (1979).
Endal, A. S. & Twigg, L. W. Astrophys. J. 260, 342–352 (1982).
Gough, D. O. in Variations of the Solar Constant (ed. Sofia, S.) 185–206 (NASA CP-2191, Washington, 1981).
Lomb, N. R. & Anderson, A. P. Mon. Not. R. astr. Soc. 190, 723–732 (1980).
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Parkinson, J. New measurements of the solar diameter. Nature 304, 518–520 (1983). https://doi.org/10.1038/304518a0
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DOI: https://doi.org/10.1038/304518a0
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