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Stellar atmospheres

Chapter 56: FOOTNOTES:
By Cecilia Payne-Gaposchkin
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About This Book

This work presents a detailed analysis of stellar atmospheres, focusing on the physical principles underlying astrophysics. It explores the relationship between physics and astrophysics, examining properties of matter related to nuclear structure and atomic states. The text discusses the stellar temperature scale, including definitions and temperature variations among different types of stars. It also addresses the effects of temperature, pressure, and other conditions on stellar spectra, providing insights into the observational results from the Harvard Observatory. The analysis aims to contribute to the understanding of stellar atmospheres through extensive research and original investigations.

Figure 9

Galactic distribution of stars mentioned in the Draper Catalogue as having narrow lines. Four sizes of dots indicate stars of different apparent magnitudes; brighter than 5.0; 5.0-6.0; 6.0-8.0; and fainter than 8.0, respectively.

This phenomenon is connected with the question of the effective optical depth of the photosphere, and is discussed in Chapter IX.

It was first pointed out by Hertzsprung[474] that the c-character marks out a class of stars with distinct physical properties—extremely small parallaxes and proper motions, strong galactic concentration, and, accordingly, very high luminosity and volume, and low density. The last feature furnishes an interpretation of the spectral peculiarities (see Chapter X).

The reality of the c-character has been questioned owing to a misapprehension as to its criteria.[475] Fine lines always accompany the c-character, but they may be present without it. The star h Ursae Majoris is a case in point. It is listed in the Henry Draper Catalogue as having narrow lines, a remark that usually indicates the presence of the c-character. Actually the star appears to be a dwarf, of Class , with considerable proper motion. Although the lines are narrow and sharp, the spectrum has not the very typical appearance of a c-star.

FOOTNOTES:

[439] E. B. Wilson and Luyten, Proc. N. Ac. Sci., 11, 133, 1925.

[440] J. S. Plaskett, Pub. Dom. Ap. Obs., 2, 287, 1924.

[441] Shapley and H. H. Wilson, H. C. 271, 1925.

[442] Van Maanen, Proc. N. Ac. Sci., 4, 394, 1918.

[443] J. S. Plaskett, Pub. Dom. Ap. Obs., 2, 147, 183, 269, 1922.

[444] J. S. Plaskett, Pub. Dom. Ap. Obs., 2, 287, 1924.

[445] Ast. and Ap., 13, 448, 1894.

[446] H. A. 28, 1900.

[447] Lick Pub., 13, 248, 1918.

[448] H. H. Plaskett, Pub. Dom. Ap. Obs., 1, 325, 1922.

[449] J. S. Plaskett, Pub. Dom. Ap. Obs., 2, 287, 1924.

[450] Payne, H. C. 263, 1924.

[451] Payne, H. C. 263, 1924.

[452] Preface, Henry Draper Catalogue.

[453] M. N. R. A. S., 83, 403, 1923.

[454] H. C. 258, 1924.

[455] Chapter IV, p. 52.

[456] Shapley, H. B. 805, 1924.

[457] Shapley, Rep. Spectr. Class. Com., I. A. U., 1925.

[458] See Appendix.

[459] Mt. W. Contr. 244, 1922; 262, 1923.

[460] H. C. 264, 1924; cf. Lindblad, Ap. J., 59, 305, 1924.

[461] Shapley, H. B. 798, 1924; Luyten, H. C. 251, 1924.

[462] Rep. Spectr. Class. Com., I. A. U., 1922.

[463] Luyten, H. B. 797, 1924.

[464] J. S. Plaskett, Pub. Dom. Ap. Obs., 2, 335, 1924.

[465] Lockyer and Baxandall, Proc. Roy. Soc., 77A, 550, 1906.

[466] Belopolsky, Pub. Ac. Imp. St. Pet., 6, 12, 1913; Pulk. Bul., 6, 10, 1915.

[467] Lockyer and Baxandall, Proc. Roy. Soc., 77A, 550, 1906.

[468] Kiess, Pub. Obs. Mich., 3, 106, 1923.

[469] Lockyer, Pub. Sol. Phys. Com., 1904.

[470] Wright, L. O. B. 332, 1921.

[471] A. C. Maury, H. A., 28, 79, 1897.

[472] Russell, Ap. J., in press.

[473] Stewart, Phys. Rev., 22, 324, 1923; Russell and Stewart, Ap. J., 59, 197, 1924.

[474] A. N., 179, 374, 1908; A. N., 192, 262, 1912.

[475] Harper and Young, J. R. A. S. Can., 18, 9, 1924.