Identifier: adolfostahllectu00astruoft (find matches)
Title: The Adolfo Stahl lectures in astronomy, delivered in San Francisco, California, in 1916-17 and 1917-18, under the auspices of the Astronomical Society of the Pacific
Year: 1919 (1910s)
Authors: Astronomical Society of the Pacific Aitken, Robert Grant, 1864-1951
Subjects: Astronomy
Publisher: San Francisco Stanford University Press
Contributing Library: Gerstein - University of Toronto
Digitizing Sponsor: MSN

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ear dimensions of thefigure for the most luminous stars are smallest, and largestfor that corresponding to the faintest stars. This agreesperfectly with the relation between absolute luminosity andspeed found in the preceding section. Next it will be seenthat the general characteristics of the three figures are thesame. The symmetrical curves all have their longest axes inlongitudes near 170° ; in this direction, which agrees well withthat of the stream motion, the average radial velocity ishighest. The curves corresponding to the velocity surfaces whichmore accurately represent the data are three-lobed, and thepreferential directions of highest velocity no longer form astraight line, but are inclined at an angle which is smallest The Brightness of the Stars 243 90 -^-srr *~~ \ / • y^ Vx^ \ 164° 1/ \ L *^ -^ ^ \ / \ \ . l79°/( ~~ ---_ \ a \ / n;--^^ V \ / ^\J^~~--_ \ . v / \^^^ ^■--7 * \ \^ / %^ / / / ^**-^ ^^^ /^v N XT / --.__ / ^ / 7H \v.^--< jy3 2 2* 256.6 2 70° Fig. 23.
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Fig. 22, 23, 24. Intersections Between the Average Radial-Velocity Surfaces and the Galactic Equator for Three GroupsOF Stars : Fig. 22, for the stars intrinsically brightest and most dis-tant ; Fig. 24, for those intrinsically faintest and nearest; Fig. 23, forthe stars intermediate in luminosity and distance. The distancesof the points from the intersection of the reference lines representthe average radial velocity in regions near the galactic equator. Theprojections of the longest axes of the surfaces are indicated by straightlines; the arrov^^s indicate the position of approximate planes of sym-metry perpendicular to the galactic equator. From the investigation byStromberg, Mt. Wilson Contr., No. 144; Astrophysical Journal, 47, 7,1918. 244 The Adolfo Stahl Lectures for the most distant stars. The arrows directed downwardbisect these angles approximately, and indicate what, for otherreasons, we believe to be the direction of the center of thestellar system. The axes of greatest mo

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