New-York tribune., 1903-04-05

o5 Obeorvatorv described three whose be
havior had been carefully studied ana Niio'V
periods were about half a day. They were Si'u
ated In a gobular cluster in Canes NehatlcI' con-
tanning something like one thousand stars Inc
same astronomer had previously pointed out
that that particular cluster. put down IN the
catalogues as "Messier g." included larger
proporton of variables than any other similar
object Almost simultaneously with these op-
seryations-possbly a little later-'he reco'u
was beaten by two stars in the southern He"'
ems also included in cluster. This cluster III
the constellation Of Centaurus. is credlteu Win
being numerically the largest known ana HI
Guiding nearly quite ten thousand stars 1"O
variables there go through one full huctuatioh
in hours IL 4 minutes, and I hours 10 lllh-
utes respectively. The latter is closely ap-
preached by a third southern star. situated III
the constellation of Anita. and having perlou
of only hours 46S minutes.
One can now understand the interest Which
astronomers will feel in the discovery announced
by Messrs. Muller and Kempf, of the Potsuam
(Prussia) Observatory. They have touhu d
variable they say. with a period only 10 SEE
onds over four hours! It's position IS near the
boundary between the Great Bear ana the LYNN
(rght ascension, 936:44; north declination,
56:24:O6). The amount of fluctuations is small
At the maximum stage of brightness the stars
MAGNITUDE is 10 and at its minimum sos; but
this difference is sufficient to justify its assign
ment to the family of variables The discover
ers think that the most satisfactory explanation
of the fuctuation { briliancy in this instance
is that two bright bodies revolving around
a point lying between Their centres in plane
whose edge is directed toward the observer Ii
this hypothesis b; correct, one body would re-
cede from the earth for short interval of time.
while the other advanced. Inasnuch as the
the line of sight, perhaps the suspicion of
Messrs. Muller and Kempf Can be verified before
many weeks.
The record for abruptness of dminution in
light has also just been broken. AS might be
expected the star of which that announcement
is made belongs to the Algol type. That is to
say its brightness is uniform throughout the
greater part of its period and then falls off rap
idly, as if there a partial eclipse by
satellite. The alteration is not gradual as with
Mira. Algol yariables are numerous, scarcely a
year passing now without several being fdeni-
fed. The character of thC one in question was
first recognized by Nine. Ceraski, Russian,
early in 1903. Her discovery arose from an ex-
animation of photographs of the heavens made
Ly Bajko, of Moscow, several weeks apart in
1890. Inasmuch as the plates had been exposed
without special reference to recording the
tremes of brightness. her examination did not
enable her to report on these with precision.
However she thought that at its maximum the
star reached the tenth magnitude, While it fell
to the twelfth at its minimum Its period she
put about eig-te n days.
When the of this work reached the Har-
ward Observatory a few weeks afterward.
hunt was instituted among the many photo
graphs made there with a Draper telescope, of
the particular region where the star was situat-
ed (right ascension p :02:20 north declination
45:22:35). This resulted in shortening the
period to l day, hours and 34.7 minutes. To
prove the accuracy of the computation, Profess
Pickering says that minimum was predict
ed and observed photographically and other
wise. 1t also discovered that the range in
brightness was a little greater than Nine Ce-
raski had been able to detect amounting to PA
made from Harvard. though, is that about half
an hour before the minimum, the rate of dini-
mutton in light amounts to between two and
three magnitudes hour. and is probably
greater than that of any other star yet dscov-
cred"
Is visible to the naked eye. The limit to most
peoples vision is at the fifth magnitude, though
sixth magnitude stars. The record
breaker for brevity of period ought to be dis
cernible in a telescope of four five inches
aperture, though unless one had become expert
in noting slight changes in brightness he would
not detect the variability.