FOOTNOTES:

i009Figure 9Galactic 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.

Figure 9Galactic 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.

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 inChapter 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. Thelast feature furnishes an interpretation of the spectral peculiarities (seeChapter 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]SeeAppendix.[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.

[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]SeeAppendix.

[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.

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