305
273, 274 ] Disturbances from Passing Stars
of the eccentricity and the period. Temporarily denoting the eccentricity by
e (to avoid confusion with e = 2*7182), we have
so that, keeping E" constant,
and eccentricities.
274. This law of distribution falls naturally into two parts, one of which,
P. This shews that in the final steady state which is obtained after a suffi
cient amount of interaction between different systems, there will be no
correlation between the periods and eccentricities of binary systems.
A very different state of things is disclosed by the tables given in § 258,
periods and eccentricities of orbits increasing together in a very marked way.
tained a statistical steady state.
This result is not altogether disadvantageous to the progress of cosmogony.
If the theoretical law of steady-state distributions had been exactly obeyed
by actual stellar orbits, we should have obtained a result which, while strik
ing and concise, would have closed the door against all further progress
in the direction in which we are now working. As it proves, the law is far
from being obeyed, and the deviations from the law, which come from the
stars not having interacted for a sufficient time, must represent surviving
vestiges of the initial conditions of the stars : they provide material, then, for
discussing the origins and early histories of binary systems. If the present
distribution of eccentricities and periods had agreed with the theoretical
steady-state law, the problem of discussing these origins and early histories
would have been comparable only to that of trying to decipher the writing
on a slate after a wet sponge had been rubbed over it. Our discussion has
shewn that the sponge was not thoroughly wet ; the writing, although doubt
less smudged, is not wholly obliterated. The eccentricities and periods have
not yet been levelled to the extent required by the theoretical steady-state
7 2 E"hdh
ed€ = -—
Using this and the further relation
the law of distribution (273‘7) takes the form
which gives the law of distribution of orbits classified according to periods
2 ede, involves only the eccentricity e, while the other involves only the period
which reveal a pronounced correlation between these two quantities, the
We must conclude that the orbits of binary stars are still far from having at-