Evening star., 1954-06-02
U. Of Virginia Studies
Sworms Of Tiny Stors
Red Dworfs' in Milky Way
Muy Be Suns Grown Old
By Thomos R. Henry


CHARLOTTESVILLE, Va.-Swarms
Of little red stars. perhaps suns grown
old. In this part Of the Milky Way gal
axy. are being studied by University Of
Virginia astronomers.
These are the red dwarfs, with masses
two-tenths to six-tenths the mass of
the sun. One Of them is Proxima Cen.
tauri. part Of the triple star Alpha
Centauri, which is the suns closest
neighbor in space, less than five light
years (more than $50 billion miles,
away. Several hundred of these stars
whose existence hitherto has been
neither known nor suspected have been
found within region Of IS light years
Of the sun by DR.. A. N. Vyssotsky Of
the university's Mccormick Observa-
tory, 1t has been announced to tho
Virginia Academy Of Sciences. Now
about 800 are known in this radius of
nearby space.
Methods developed here for analyz-
ing the light spectra of these stars now
make it possible to determine their
masses and distances in few minutes.
whereas formerly this would have re-
quired several years spent In observ-
ing movements. Some are moving very
fast-about 500 miles O second com.
pared to the IL miles o second with
which the sun. dragging its planets
with it. is moving toward the con-
stellation Of Hercules.
In the past it has been assumed that
those with apparently great speeds were
nearby stars. BY analyzing their light as
the wave lengths shift according to the
speed and direction of motion. however,
DR.. VySSotsky and his associates have
found that some of the nearest red
dwarfs apparently are almost standing
still with respect to the sun.
New Evidence.
The normal assumption in the past
was that the red dwarfs once were stars
of about the mass and brightness of the
sun. much of whose substance has been
burned away in the complicated trans
mutation process of hydrogen into he
lium. and which now are on their way
to becoming celestial cinders.
Some Of the Mccormick Observatory
observations, however, indicate that the
red dwarfS may be at the other end of
the evolutionary Scale--newborn stars
which eventually will build up to bodies
as big as the sun, about the average
star size in the Milky Way galaxy.
In the constellation Of Orion, about
lis light years distant in space, is the
strange triple star. Mu Orionis, which
seems to be contradicting some of the
best established laws of the universe.
DR.. Harold L. Alden. director of the Nc
Cormick Observatory, has been follow
ing it for more than 40 years.
Three stars constitute one compact
little family which usually is referred to
as single heavenly body. It can be
seen with the naked eye. Its brightness
fluctuates quite markedly in periods Of
"A days. This Is due to q small star
moving around a very bright star in
this time. The two together have little
more mass than the sun.
Mu Or1oniS has smaller fluctuations
in brightness in periods Of 18 years and
three months. This is due to the third
star Of the system moving around the
other two. Its distance from them is
about 10 times that of the earth from
the sun. 1t is only about a tenth as
bright as the other two combined. But,
says DR.. Alden. observations now show
that 1t is almost as big and about equal
to the sun in size. All three stars in
the system are approximately the same
distance away. Hence their brightness
should depend on their mass. This is
perhaps the most fundamental meas
uring stick In astronomy.
Star Burning Out.
A possible explanation. says DR.. AL
den, is that some stars burn up much
faster than others and that the two fold
bright object in Mu Orionis is con-
Suming itself rapidly whereas the
third object is burning slowly. II this
chests is accepted. 1t may make neces-
sary quite radical re-estimates of stel-
lar distances and magnitudes.
There are approximately a hundred
billion stars in the Milky Way system.
1t has been customary to consider them
in classes and assume that every star
in certain class has about the same
sort of behavior.
Now, says DR.. Alden, there is q chang
ing concept that every star is an indi-
vidual with its own idiosyncracies and
eventually will be studied as an indi-
vidual, rather than as a statistical unit.