Historical Information on Solar Abundances of the Elements

Historical Info    Evidence     Conclusions

    Noting that the Earth's crust and the Sun's gaseous envelope may not represent the overall compositions of these bodies, Harkins [1] showed in 1917 that 99% of the material in ordinary meteorites consists of seven, even-numbered elements - Fe, O, Ni, Si, Mg, S and Ca.   He concluded that "... in the evolution of elements much more material has gone into the even-numbered elements than into those which are odd ..." (p. 869).   In the 1920s, Payne [2] and Russell [3] showed that the solar atmosphere is mostly H and He, and in 1938 Goldschmidt [4] proposed an abundance table based on stellar spectra for volatile elements and on meteorites for nonvolatile elements.   However, Hoyle [5] and other astronomers continued to believe until the end of World War II that "... the Sun was made mostly of iron ..." (p. 153).   Research on H-fusion at Los Alamos during the War [6] likely aided their conversion.

    Goldschmidt's proposed loss of light, volatile elements from meteorites and rocky planets [4] is reasonable from the view of cosmic evolution, but from the view of nuclear physics the difference between an Fe-rich and a H-rich Sun is drastic.  Iron is an even-numbered element.   It consists mostly of Fe-56, with an ordinary charge density, Z/A = 0.46, and the lowest [7] mass per nucleon, M/A. Hydrogen is an odd-numbered element.   It consists mostly of H-1, with the highest values of Z/A and M/A among stable nuclides [7].   The H-rich Sun thus violates, on a grand scale, Harkins' prediction [1] (p. 859) that "... the more stable atoms should be more abundantly formed ...", but fine structure abundance peaks are still assigned to nuclear stability (e.g., Suess & Urey [8]).   To explain an H-rich Sun, Burbidge et al. [9] and Cameron [10] assumed that the products of nucleosynthesis were mixed back into the interstellar medium before the solar system formed.

    The discovery [11] of radiogenic Xe-129 in meteorites [12] severely constrained the time for mixing.   The mixing time essentially vanished as Reynolds' mass spectrometer [13] and others revealed the decay products of many short-lived nuclides and isotopic anomalies from nucleosynthesis as regular components of meteorites.   As a graduate student, Manuel joined Kuroda's effort to decipher isotope abundances in 1960, and in 2000 he officially retired as Professor and Department Chairman.  The evidence he found for an iron-rich Sun is summarized in Section II, in a 1998 review [14], and in the proceedings of an ACS symposium [15] organized by Seaborg and Manuel in August, 1999.   The conclusion that a hydrogen-filled Sun is obsolete, related observations, and the status of work on remaining issues are given in Section III.

References: [1] Harkins W.D. (1917) J. Am. Chem. Soc. 39, 856-879; [2] Payne, C.H.(1925)Stellar atmospheres (Harvard Observatory Monograph #1, Cambridge, MA, USA) pp.177-189; [3] Russell, H.N. (1929) Ap. J. 70, 11-82; [4] Goldschmidt V.M.(1938) Geochemische Verteilungsgestze der Elemente. IX. Die Mengenverhältnisse der Elemente und der Atom-arten, Skrifter Norske Videnskaps-Akad., Oslo I Math.-Naturv. Klasse, no. 4, 148 pp; [5] Hoyle F. (1994) Home is where the wind blows (University Science Books, Mill Valley, CA, USA) pp. 153-154; [6] Teller E.(1987) Better a shield than a sword (Macmillian, Inc., New York, NY, USA) p. 70; [7] Tuli J.K.: 2000, Nuclear wallet cards (Sixth edition, National Nuclear Data Center, Brookhaven National Laboratory, Upton, NY, USA) 74 pp; [8] Suess H.E. & Urey H.C. (1956) Rev. Mod. Phys. 28, 53-74; [9] Burbidge E.M., Burbidge G.R., Fowler W.A. & Hoyle F. (1957) Rev. Mod. Phys. 29, 547-650; [10] Cameron A.G.W.(1957) Publ. Astron. Soc. Pac. 69, 201-222; [11] Reynolds J.H. (1960) Phys. Rev. Lett. 4, 8-10; [12] Fowler W.A., Greenstein J.L. & Hoyle F. (1961) Am. J. Phys. 29, 393-403; [13] Reynolds J.H. (1956) Rev. Sci. Instruments 27, 928-934; [14] Origin of Elements in the Solar Sysyem: Implications of Post-1957 Observations, Proceedings of the 1999 ACS symposium organized by Glenn T. Seaborg and Oliver K. Manuel (Kluwer Academic/Plenum Publishers, New York, NY, USA, ed., O.K.Manuel, 2000), 646 pp.; [15] Manuel O.K., Lee J.T., Ragland D.E., Macelroy J.M.D., Li, Bin, Brown & W. K. (1998) J. Radioanal. Nucl. Chem. 238, 213-225.