The Columbian. [volume] (Bloomsburg, Pa.) 1866-1910, 1896-02-06


made at the Harvard College observa-
tory station at Arequipa, of the exist
ence in certain star clusters of an ex-
traordinary number of variable stars,
is one of the most remarkable of recent
astronomical advances. No less than
eighty-seven stars in the well-known
globular cluster Messier 3, in the con-
stelation Canes Venatici, have been
proved by these photographs to be var
liable; and the variation is, in some
cases, not only large, but exceeding
rapid. Some of the stars affected
change in the course of a few hours as
much as two entire magnitudes; that
is to say such stars, at the beginning
of their swift decline, are six times as
bright as at the end of 1t. But imme-
diately they commence to brighten
again. and continue to revive until they
are as bright as ever.
Hitherto most of the variable stars
observed have been found scattered
broadcast in the sky, apparently un-
connected with one another, although
there are certain regions-one, for in
stance, in Virgo-where they especially
abound. There has never been any
reason to suppose that some of the
stars in clusters might not be change
able, and, in fact a few variables have
before this been discerned in such situ-
atoms. But the Arequipa discovery
now reveals the interesting fact that,
in some star clutters, the ratio of the
number of variables to the total num-
Der of stars included In the cluster is
so great as irresistibly to suggest the
existence therein of a special cause of
variability. Prof. Pickering remarks
that 10 Of do
among the stars visible to the naked
eye is only per cent. yet in the clus-
ter n. G. c. 5,904, out of $50 stars separ-
ately examined on the Arequipa mega
tives, forty-six, or about per cent. of
the whole, have proved to be variable
And in the same cluster there seems to
be curious tendency to local aggrega-
ton of the variables, for in a circle ITO
seconds in diameter, including sixteen
stars, no less than six, or nearly 40 per
cent, are variable.
Is variation. then, a special charac-
teristic OF stars assembled in close clus-
ters? 1t would appear not: for, while
some clusters photographed at Are
quipa abound in variable stars, other
clusters, just as crowded, have as yet
given no evidence of the existence of a
single variable. But Prof Pickering
reminds us that this negative evidence
can only be taken to show that the
clusters concerned contain no variables
of short period. By continuing the
series of photographs for a sufficient
length of time long period variables
might be discovered in such assem-
blages. But even then 1t would be evil
dent that a striking difference exists in
this respect. between different clusters
M.
ly through their changes and others
only stars that vary slowly. 1t is from
differences as well as from resem-
blances that causes are to be deduced.
One thing is much to be regretted. Ow-
ing to the fact that in the middle of a
globular cluster the light of the swarm
ing stars runs into blaze. amid which
1t is practically impossible to distin-
guish separate points of light, no vari-
ables have been detected close to the
centre of any cluster
Mr.. Lockyer will probably find in this
discovery "a confirmation of his meteor
ic hypothesis, according to which vari-
able stars are swarms OF clashing me-
teors In various stages of condensation.
Speaking broadly. every star 40 doubt.
has its attendant meteor streams, and.
where large numbers of stars are as
sembled IN comparatively close prox-
imity, the possibility of meteoric col
lisions may be increased. At any rate.
such phenomena as the successive out
bursts exhibited by the new star In
Auriga few days ago indicate that
there is an amount of wrack and ruin
In the administration of the universe
at the sight of which some of the older
astronomers, who perceived only
smooth-running wheels In the celestial
mechanism, would have stood aghast.
While we are awaiting an explanation
of the causes underlying the phenom-
ena which form the object of this latest
achievement of astronomical photog.
raphy, we may again congratulate the
astronomers on their acquisition Of an
instrument of research so penetrating,
powerful and undissemeling as the
camera New Yock sun,