Evening star., 1938-05-08
YERKES TO STUDY
WHITE DWARFS
Study May Reveal Earth Is
. Surrounded by Dense
Freezing Stars.
By the Associated Press,

freeZlng stars.
By the Associated Press.
WILLIAMS BAY, Wis, May T.
Scientists at the University Of Chica-
go's Yerkes Observatory today outlined
q four -faceted project which may dis
close q preponderance of small. excess
sively dense stars in the universe.
> Such a preponderance would mean
that the earth is surrounded by heav-
enly bodies which are far hotter than
the sun although they are freezing"
They are so heavy cubic inch OF
their gas weighs a ton.
These small heavyweights of the
universe-known to science as white
dwarfs"-have always been mystery
to astronomers, Dr. Otto Struve, Rus
sian-born director Of the observatory,
explained. and the purpose of the
Yerkes study is to solve this mystery.
Physicists say the white dwarfs"
consist of a degenerate state of matter,
behaving differently from other stars.
This difference, DR.. Struve said, Is
analogous to that which takes place
In Q liquid when it freezes.
Nine or Ten Discovered.
"Our problem" the director said,
twill be to try to discover all the white
dwarfs in existence in certain vol
ume of space, a sphere, say, OF so or
100 light years. This work is in the
charge of DR.. G. P. Kuiper of the
Yerkes staff At present astronomers
don't know how frequent these white
dwarfs are. or whether they are freaks
or common bodies. The or 10
known white dwarfs have been dis
covered by chance, mostly by DR..
Kuiper.
1T is entirely conceivable that the
white dwarfs are the normal type of
structure in the universe and that
stars like our sun are the less COM
mon"
DR.. Struve described the white
dwarfs as very unusual stars, much
the same as the sun in masses, but
very small ard having temperature
considerably higher than that of the
solar body. Although some of them
are no larger than the earth, they
represent. he said, tremendous den-
sity of matter.
THE reason that cubic inch of
these stars gases may weigh ton or
more is compression. In the dwarfs,
gas is several thousand times more
compressed than the densest substance
known on the earth.
Will Photograph Star.
"Their condition. said DR.. Struve,
sis of very great interest to both as
tronomers and physicists, who must
know the kind of matter making up
the white dwarfs in order to interpret
their nature"
The first phase in the observatory's
program is construction of a special
20-inch telescope with which the SCI
entists hope to photograph very faint
stars over large area of the sky. De-
veloped under the supervision of Prof
George Van Biesbroeck, it is being con-
structed partly from funds turned over
to the observatory by Chicago's A Gen.
tury of Progress.
Based on a new principle of con-
struction, the instrument will be fitted
with a 20-inch mirror, in front of
which will be slightly curved glass
plate. This arrangement will give
wide-angle photographs. Ordinarily a
telescope can see" only very small
patch of sky and has to be shifted
The telescope will be installed on
mount Locke. site of the Mcdonald
Observatory of the University of Texas,
with which the University of Chicago
has a cooperative arrangement.
Wants More Powerful Lens.
DR.. Struve said he hoped the sue
cess Of the 20-inch instrument would
be so great well be able to build an
even more powerful telescope"
THE second important development
In our program" the director said, is
the work of DR.. w. w. Morgan, which
deals with the determination of the
brightness and distances Of stars by
means of their spectra. DR.. Morgan
discovered some time ago that the as
tronomer can tell from the spectra of
stars how much light each star emits
in space.
If we know at the same time the
brightness of the star as it appears to
us. the ratio of these two quantities.
that Is, the actual and apparent
brightness-givesu us the distance.
Given the new telescope and
faster and more accurate method Of
determining the distances of stars, our
third phase is the finding from all
observed stars those that are white
dwarfs."
Mathematics Is Strives Job.
To the theoretician is assigned the
closing chapters of these stellar inves-
legations. Heading this work Is DR..
s. Chandrasekhar Of India, assistant
professor in astrophysics and leading
authority in the Interpretation of the
white dwarf type of star.
The job OF correlating the activities
and presenting the abstruse and ap-
pallingly mathematical findings in
broad terms falls to the leadership of
Director struve.