Proceedings of the Section of Sciences - Koninklijke Academie
van Wetenschappen -- te Amsterdam, 16, 395 (1913).
Astronomy. -- "On the constancy of
the velocity of light". By
We have then, using the notations of my former paper
1 Astronomische Kriterien für die Unabhängigkeit der
Dortplanzungsgeschwindigkeit des Lichtes von der Bewegung der
Lichtquelle, Astr. Nachr. 4670
[*] Δ represents the distance from a double star to an observer.
where naturally u, uo, c, Δ, τ, and T must all be expressed in the same units (km. and sec.) The observed velocities will thus show a spurious excentricity, of the amount
Now it is easy to derive an upper limit for x. Take a well known star like β Aurigae. The observations give
e < 0.015,
Quite possibly other stars will give smaller values of x. The smallest values, of course, are found from the stars having the smallest parallaxes. Unfortunately the parallax of most spectroscopic doubles is still unknown, and it is thus impossible to give numerical values. We can however assume as certain that for the majority of these stars a value would be found which is still smaller than that given above.
Postscript. During the discussions at the meeting the remark was
made (by Prof. Korteweg) that the star
might have a true
excentricity of such amount as exactly to cancel the spurious excentricity
produced by the motion. This is, of course, entirely correct. If this
true excentricity 1 were e = 0.90 we should find
x = 0.12, [taking again p = 0".05 and using the same
approximate formula as above, though this is not correct for such large
excentricities]. Thus if we knew only this one star, we should have to
adopt as upper limit for x this value 0.12. There are however a
considerable number of stars with large values of uo,
whose observed excentricity is very small or zero. Several of these
certainly have very small parallaxes. It would evidently be absurd to
assume that all of these possessed exactly that true excentricity and
position of the periastron which would cancel the apparent excentricity
for an observer on our earth.
1 For β Aurigae a large excentricity is particularly improbable on account of the presumably large dimensions of both components as compared with their mutual distance.
Assistance was provided by the Interlibrary Loan Services at
Mississippi State University's Mitchell Memorial Library and
The Smithsonian Institution Libraries in obtaining a copy of
the original "Proceedings" article.
Installed 01 Jun 2006.
Shade Tree Physics