Binary
Stars -Introduction
[Physics
of Binary Stars] [Binary Star Case
Study]
[Binary
Star Data]
The brightest
objects in the night sky apart from the moon and planets are binary and
tertiary star systems. These are systems of two or three stars so close
together that they orbit a common center
of gravity. Due to their distance they appear on earth to the naked eye
as one very bright object. A large number of known stars occur in these
groups, inculding our nearest neighbour Alpha Centauri. They produce some
of the most vivid sights of the night sky. There are three types :
-
Visual Binaries
-
Spectral Binaries
-
X ray binaries
Visual
Binaries are far enough
apart to be seen as two separate bodies.
Spectral
Binaries are so close that they
appear as one single star. They can only be differentiated by the doppler
shifts in their emitted light. Since they are continually eclipsing each
other the binary star appears to bulge and contract. See Binary
Star case Study
X ray
binaries are the third
type exists where one of the pair collapses and forms a black hole and
will pull matter away from its neighbour. As this matter falls towards
the black hole it heats up and starts to emit a lot of light in most regions
of the EM spectum but especially in the X ray region. Examples of this
phenomena and others are shown , with many others present at the photo
galleries of institutions like NASA
Binary stars are useful
in that they allow astronomers to estimate distances in space. If an estimate
of the mass of the stars is made and the time
of orbit measured then the radius of the orbit of the stars can
be calculated by applying Newtonian mechanics.
Using this information and the observed angle between
the stars on earth an estimate of distance between earth and the star can
be made.
[Physics
of Binary Stars] [Binary Star Case
Study]
Back
To The Top