Abstract

A brief history is given of astronomical observations of the spectra of heavy elements in stars, with emphasis on those elements produced by slow capture of neutrons in the stellar interior. As an example, an abundance analysis of the electrons zirconium through ruthenium, including the unstable element technetium, is described. Schemes for explaining the presence of technetium (probably 99Tc with a half-life of 2 × 105 years) and the presence of niobium (formed by decay of 93Zr with a half-life of 1.5 × 106 years) are discussed. The importance of radioactive decay of technetium from an excited nuclear state is stressed.

© 1984 Optical Society of America

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References

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  1. H. N. Russell and W. S. Adams, Astrophys. J. 68, 9 (1928).
    [CrossRef]
  2. C. E. St. John and C. E. Moore, Astrophys. J. 68, 93 (1928).
    [CrossRef]
  3. P. W. Merrill, Astrophys. J. 56, 457 (1922).
    [CrossRef]
  4. P. W. Merrill, Astrophys. J. 65, 23 (1927).
    [CrossRef]
  5. P. C. Keenan, Astrophys. J. 97, 101 (1942).
    [CrossRef]
  6. W. P. Bidelman and P. C. Keenan, Astrophys. J. 114, 473 (1951).
    [CrossRef]
  7. P. W. Merrill, Astrophys. J. 115, 484 (1952).
  8. A. G. W. Cameron, Astrophys. J. 121, 144 (1955).
    [CrossRef]
  9. J. L. Greenstein, in Modern Physics for Engineers, L. Ridenour, ed. (McGraw-Hill, New York, 1954), p. 267.
  10. H. E. Suess and H. C. Urey, Rev. Mod. Phys. 28, 53 (1956).
    [CrossRef]
  11. V. V. Smith and G. Wallerstein, Astrophys. J. 273, 742 (1983).
    [CrossRef]
  12. R. H. Garstang, Publ. Astron. Soc. Pac. 93, 641 (1981).
    [CrossRef]
  13. E. Anders, Astrophys. J. 127, 355 (1958).
    [CrossRef]
  14. C. H. Corliss and W. R. Bozman, Nat. Bur. Stand. (U.S.) Monogr. 53 (1962).
  15. M. Schwarzschild and R. Harm, Astrophys. J. 150, 953 (1967).
    [CrossRef]
  16. R. H. Sanders, Astrophys. J. 150, 971 (1967).
    [CrossRef]
  17. I. Iben, Astrophys. J. (to be published).
  18. A. G. W. Cameron, Astrophys. J. 130, 452 (1959).
    [CrossRef]
  19. G. Schatz, Astron. Astrophys. 122, 327 (1983).

1983 (2)

V. V. Smith and G. Wallerstein, Astrophys. J. 273, 742 (1983).
[CrossRef]

G. Schatz, Astron. Astrophys. 122, 327 (1983).

1981 (1)

R. H. Garstang, Publ. Astron. Soc. Pac. 93, 641 (1981).
[CrossRef]

1967 (2)

M. Schwarzschild and R. Harm, Astrophys. J. 150, 953 (1967).
[CrossRef]

R. H. Sanders, Astrophys. J. 150, 971 (1967).
[CrossRef]

1962 (1)

C. H. Corliss and W. R. Bozman, Nat. Bur. Stand. (U.S.) Monogr. 53 (1962).

1959 (1)

A. G. W. Cameron, Astrophys. J. 130, 452 (1959).
[CrossRef]

1958 (1)

E. Anders, Astrophys. J. 127, 355 (1958).
[CrossRef]

1956 (1)

H. E. Suess and H. C. Urey, Rev. Mod. Phys. 28, 53 (1956).
[CrossRef]

1955 (1)

A. G. W. Cameron, Astrophys. J. 121, 144 (1955).
[CrossRef]

1954 (1)

J. L. Greenstein, in Modern Physics for Engineers, L. Ridenour, ed. (McGraw-Hill, New York, 1954), p. 267.

1952 (1)

P. W. Merrill, Astrophys. J. 115, 484 (1952).

1951 (1)

W. P. Bidelman and P. C. Keenan, Astrophys. J. 114, 473 (1951).
[CrossRef]

1942 (1)

P. C. Keenan, Astrophys. J. 97, 101 (1942).
[CrossRef]

1928 (2)

H. N. Russell and W. S. Adams, Astrophys. J. 68, 9 (1928).
[CrossRef]

C. E. St. John and C. E. Moore, Astrophys. J. 68, 93 (1928).
[CrossRef]

1927 (1)

P. W. Merrill, Astrophys. J. 65, 23 (1927).
[CrossRef]

1922 (1)

P. W. Merrill, Astrophys. J. 56, 457 (1922).
[CrossRef]

Adams, W. S.

H. N. Russell and W. S. Adams, Astrophys. J. 68, 9 (1928).
[CrossRef]

Anders, E.

E. Anders, Astrophys. J. 127, 355 (1958).
[CrossRef]

Bidelman, W. P.

W. P. Bidelman and P. C. Keenan, Astrophys. J. 114, 473 (1951).
[CrossRef]

Bozman, W. R.

C. H. Corliss and W. R. Bozman, Nat. Bur. Stand. (U.S.) Monogr. 53 (1962).

Cameron, A. G. W.

A. G. W. Cameron, Astrophys. J. 130, 452 (1959).
[CrossRef]

A. G. W. Cameron, Astrophys. J. 121, 144 (1955).
[CrossRef]

Corliss, C. H.

C. H. Corliss and W. R. Bozman, Nat. Bur. Stand. (U.S.) Monogr. 53 (1962).

Garstang, R. H.

R. H. Garstang, Publ. Astron. Soc. Pac. 93, 641 (1981).
[CrossRef]

Greenstein, J. L.

J. L. Greenstein, in Modern Physics for Engineers, L. Ridenour, ed. (McGraw-Hill, New York, 1954), p. 267.

Harm, R.

M. Schwarzschild and R. Harm, Astrophys. J. 150, 953 (1967).
[CrossRef]

Iben, I.

I. Iben, Astrophys. J. (to be published).

John, C. E. St.

C. E. St. John and C. E. Moore, Astrophys. J. 68, 93 (1928).
[CrossRef]

Keenan, P. C.

W. P. Bidelman and P. C. Keenan, Astrophys. J. 114, 473 (1951).
[CrossRef]

P. C. Keenan, Astrophys. J. 97, 101 (1942).
[CrossRef]

Merrill, P. W.

P. W. Merrill, Astrophys. J. 115, 484 (1952).

P. W. Merrill, Astrophys. J. 65, 23 (1927).
[CrossRef]

P. W. Merrill, Astrophys. J. 56, 457 (1922).
[CrossRef]

Moore, C. E.

C. E. St. John and C. E. Moore, Astrophys. J. 68, 93 (1928).
[CrossRef]

Russell, H. N.

H. N. Russell and W. S. Adams, Astrophys. J. 68, 9 (1928).
[CrossRef]

Sanders, R. H.

R. H. Sanders, Astrophys. J. 150, 971 (1967).
[CrossRef]

Schatz, G.

G. Schatz, Astron. Astrophys. 122, 327 (1983).

Schwarzschild, M.

M. Schwarzschild and R. Harm, Astrophys. J. 150, 953 (1967).
[CrossRef]

Smith, V. V.

V. V. Smith and G. Wallerstein, Astrophys. J. 273, 742 (1983).
[CrossRef]

Suess, H. E.

H. E. Suess and H. C. Urey, Rev. Mod. Phys. 28, 53 (1956).
[CrossRef]

Urey, H. C.

H. E. Suess and H. C. Urey, Rev. Mod. Phys. 28, 53 (1956).
[CrossRef]

Wallerstein, G.

V. V. Smith and G. Wallerstein, Astrophys. J. 273, 742 (1983).
[CrossRef]

Astron. Astrophys. (1)

G. Schatz, Astron. Astrophys. 122, 327 (1983).

Astrophys. J. (13)

H. N. Russell and W. S. Adams, Astrophys. J. 68, 9 (1928).
[CrossRef]

C. E. St. John and C. E. Moore, Astrophys. J. 68, 93 (1928).
[CrossRef]

P. W. Merrill, Astrophys. J. 56, 457 (1922).
[CrossRef]

P. W. Merrill, Astrophys. J. 65, 23 (1927).
[CrossRef]

P. C. Keenan, Astrophys. J. 97, 101 (1942).
[CrossRef]

W. P. Bidelman and P. C. Keenan, Astrophys. J. 114, 473 (1951).
[CrossRef]

P. W. Merrill, Astrophys. J. 115, 484 (1952).

A. G. W. Cameron, Astrophys. J. 121, 144 (1955).
[CrossRef]

V. V. Smith and G. Wallerstein, Astrophys. J. 273, 742 (1983).
[CrossRef]

E. Anders, Astrophys. J. 127, 355 (1958).
[CrossRef]

M. Schwarzschild and R. Harm, Astrophys. J. 150, 953 (1967).
[CrossRef]

R. H. Sanders, Astrophys. J. 150, 971 (1967).
[CrossRef]

A. G. W. Cameron, Astrophys. J. 130, 452 (1959).
[CrossRef]

Publ. Astron. Soc. Pac. (1)

R. H. Garstang, Publ. Astron. Soc. Pac. 93, 641 (1981).
[CrossRef]

Rev. Mod. Phys. (1)

H. E. Suess and H. C. Urey, Rev. Mod. Phys. 28, 53 (1956).
[CrossRef]

Other (3)

I. Iben, Astrophys. J. (to be published).

C. H. Corliss and W. R. Bozman, Nat. Bur. Stand. (U.S.) Monogr. 53 (1962).

J. L. Greenstein, in Modern Physics for Engineers, L. Ridenour, ed. (McGraw-Hill, New York, 1954), p. 267.

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Figures (3)

Fig. 1
Fig. 1

The neutron-capture chain from zironium to ruthenium showing the decays of 93Nb and 99Tc. Half-lives of unstable isotopes are indicated.

Fig. 2
Fig. 2

Intensity tracings of two heavy-element stars, one of which, CY Cyg, shows a TcI line and one of which, HD 121447, does not.

Fig. 3
Fig. 3

Nuclear-energy levels of 99Tc and 99Ru showing the 140.5-keV level of 99Tc that is appreciably populated by the Boltzmann distribution at sufficiently high temperatures.

Tables (2)

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Table 1 Abundances of Various Elements in Six Heavy-Element Starsa

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Table 2 Mean Abundances of Heavy Element

Equations (2)

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d N A / d t = N n ( N A - 1 σ v A - 1 - N A σ v A )
N A - 1 N A = σ v A σ v A - 1 ,

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