A "spectroscopic" binary is one in which the two stars cannot be seen separately even with a telescope. They are very close together and move around each other very quickly, over a period of a few weeks or even a few days. However, they can be seen to be two separate stars by using a spectroscope, which is able to record the Doppler change in the color of the light sent out by stars moving quickly toward or away from the Earth.
Some spectroscopic binaries have an orbit that is edge-on to Earth. When this happens, the stars will take turns passing in front of and eclipsing the partner star, in what is called an "eclipsing binary". In this case, the amount of light we see from the double dims slightly during the time one star is in front of the other.
An "astrometric binary" is one where only one companion can be seen. For astrometric binaries fairly near the Earth (up to about 10 parsecs), it may be possible to see the visible companion "wobble" as it moves around its invisible companion. By making measurements over a long period of time, it may be possible to calculate the mass of the visible star and how long its orbit takes. This method is also used to detect the presence of large planets orbiting a star; as of 2007, over two hundred planets have been discovered in this way.
Most binaries are "detached binaries". Except for their gravitational pull on one another, they have no effect on each other.
Some binaries are so close to one another that one or both stars is able to pull material from the other. Contact binaries share the same stellar atmosphere, and as friction slows them over a long period, they may merge into one star. This violent event temporarily makes them shine more brightly, brighter than a nova but less bright than a supernova.
Though it could be possible that binary stars may form when one star passes very close to another, it is highly unlikely (since it would actually take three stars close to one another before two could join), and would occur only in places where stars are densely packed together. Our present understanding is that almost all binaries are formed together in the dense gas clouds where stars are born.
It is possible (though not likely) that a passing star will disrupt a binary system and provide enough gravitational force to split the binary. Such separated stars go on to live lives as ordinary single stars. Sometimes, though, enough gravitational force is involved that the two companions speed away from each other at great speeds, resulting in what is known as "runaway" stars.
Sometimes a star is in orbit around a white dwarf star. If it is large enough and close enough to the white dwarf, the dwarf may suck gasses from its companion's atmosphere. Over a period of time, a great deal of gas may collect on the white dwarf. As this gas is compacted by the white dwarf's gravity, it will eventually undergo nuclear fusion, resulting in a very bright outburst of light, known as a "nova". In some cases, the white dwarf may gather so much gas that the explosion completely destroys it, in what is called a "supernova". Such an event may also result in runaway stars, as the larger star no longer has a heavy companion which keeps it in orbit.
X - Ray Binaries produce great amounts of X-ray radiation. They result from a massive star eating a less massive star. The lesser star becomes a donor and its matter is drained out and falls into the more massive (but more compact) star, the accretor. This releases high energy photons, for example in the X-Ray range of wavelengths. The X-Rays also come from the consumption of material on the surface of the more massive star in a process called thermonuclear burning. This can make 10 second bursts.
Imperial units
The Imperial units or the Imperial system is a collection of measurement units. An Act of Parliament in 1824 created it from traditional English units. Commonwealth countries used this system from 1824 until they changed to the metric system. The imperial system is very similar to the American system but there are some differences.
The British nautical mile used to be 6080 feet. In 1970 the UK adopted the international definition of 1852 metres.
The full table of "British apothecaries’ measure" is:
For a comparison to the United States customary units see the article on Comparison of the Imperial and US customary systems.
Comparison of the Imperial and US customary systems
The imperial and U.S. customary systems are similar, but there are some differences between them.
The main difference is in units of volume. The American system has two gallons: a wet and a dry one. The imperial gallon is bigger than each of these. However, the imperial fluid ounce is slightly smaller than the American one.
The international yard is exactly 0.9144 metres. This definition was agreed upon by the United States, Canada, the United Kingdom, South Africa, Australia and New Zealand in 1959. However, the United States continued to use its old length units for surveying purposes. The US survey foot is exactly 36/39.37 metre.
Another difference is in units of mass. In Britain people often use the stone. One stone is 14 pounds. Eight stones are one hundredweight (112 lb). Twenty hundredweights are one ton. So one British ton is 2240 pounds. It is very close to the tonne of the metric system.
In the United States people do not use the stone. They usually use a hundredweight of 100 pounds. This hundredweight is also called a "short hundredweight". Twenty short hundredweights are one short ton. The British hundredweight is also called the "long hundredweight" and the Britsh ton is also called the "long ton".
Stone (unit)
The stone is a unit for measuring mass in the Imperial system. It is equal to fourteen pounds. 160 stone make up a long ton. In the metric system, 1 stone = 6.35029318 kilograms.
The short way of writing stones is st.
The stone was outlawed in Ireland and the United Kingdom, in 1983 and 1985 respectively. However stones and pounds are both commonly used in non-official cases, most commonly when stating the weight of a person. Often in American-British boxing matches, the contenders  weight is stated in pounds then stones and pounds. The same in horse racing.
Maccabi Haifa F.C.
Maccabi Haifa Football Club (, "Moadon HaKaduregel Maccabi Haifa") is an Israeli football team from the city of Haifa, a section of Maccabi Haifa sports club. The club has won 11 championships, 5 State Cups and 3 Toto Cups. The club was founded in 1913, and it is one of the country's most successful teams in Europe, being the first Israeli club to qualify for the group stage of the UEFA Champions League.
Maccabi Haifa Football Club was established in 1913 in the port city of Haifa. It was a small, struggling club that spent most of its time bouncing between the Liga Leumit and the lower leagues.
The club was overshadowed by their city rivals Hapoel Haifa, who were then the darling club of the city of Haifa and especially of then mayor Abba Hushi. But even in its first years the club adapted a very adventurous and offensive style of play based on technique and short passes. In 1942, the club reached the Israel State Cup final, but was humiliated 12-1 by Beitar Tel Aviv in the final, which is the club's worst defeat ever. In 1962, the club won its only honour until the 80s, when the team defeated Maccabi Tel Aviv 5-2 in the State Cup final. In 1963 they reached the final again, but failed to defend their title losing to arch-rivals Hapoel Haifa 1-0.
Maccabi Haifa F. C. is a professional football (soccer) club in Israel. Founded in 1913, it is Israel's most successful club both domestically and in European competitions.
Leagues Won
Cups Won
Avi Ran,
Adoram Keisi,
Eyal Berkovic,
Yaniv Katan,
Yossi Benayoun,
Reuven Atar and
Alon Mizrahi
Most Goals in season - 1993/1994
Most Games played without losing strike - 46 Games (From Seasons 1993-1995)
Most Away Undefeated Strike - 30
Most Points in a Year - 96 Points