Bright star in the night sky. The most is a fixed star. The fixed star means the star that twinkles voluntarily like the sun. The fixed star on the outline in the appearance exists little shifting position on the celestial globe. The fixed star was examined from various angles.
Brightness of fixed star
Hipparukosu who is the astronomer in ancient Greece, in the star such
as one, the brightest star that was looked and gotten made the darkest
star a star such as six. It was assumed that the star such as one was brightness
100 times the star such as six in the 19th century afterwards. The brightest
star is a star in the α star sirius of the seat such as -1.4 now excluding
the sun though the definition seems to be a little different.
Name of fixed star
Some names like a Bayer name, Flamsteed number, and a peculiar name, etc. are given to the fixed star. It is Altair, and peculiar name and α(alpha) star and β(beta) stars are the Bayer names though three fixed stars that are called a great triangle in summer for instance are called "Deneb → Cygnus α(alpha) star in Cygnus", "Altair → Aquila α(alpha) star in Aquila", and "Vega → Lyra α(alpha) star in Lyra". say Vega
The Sun
The sun is a fixed star that exists in the shortest distance to the earth.
There are 6000℃ temperature, and the main atmosphere is made of hydrogen and helium. Please look at the page of the sun in detail.
Galaxy
Galaxyis a large population from such stellar and interstellar material.
The size is overcrowded within the range of the diameter several hundred
thousand light-year wide in the most basic object of space following the
fixed star.
※Light-year … Unit that shows distance to fixed star
……Light is a distance in one year advanced in the vacuum. Because
the speed of light is about 300,000km/s, it becomes one light-year
= about 9.4 trillion km.
Various galaxy
Elliptical galaxy
It is one of the classifications of galaxy in the fixed star who is a large group. It is distinguished from whirlpool [jouginga] and the irregular galaxy. This elliptical galaxy is made from an old star in a young star and exist in no content of the gas and Chile.
Swirling galaxy
It has the whirl structure, the fixed star and the interstellar matter
gather in discoid, and the swirling galaxy is made. Concentration by gravity
balances the centrifugal force by the rotation of the disk, and shape can
be kept.
Nebula
It is a gas that consists of the cosmic dust and the interstellar gas,
etc. with the settlement in gravity it is tossed about space. It is distinguished
now though it seems to have been thought that the Milky Way was one of
the nebulas before.
（The right picture is Great Nebula of Orion.）
Rose nebula
The rose nebula is a nebula where it is in 4600 light-years, and is born the fixed star. It is red and called the rose nebula as if the flower.
Galactic system
In about 200 billion fixed stars, the galactic system seen in the Milky
Way seen from the earth is groups.
Miscellaneous thought
It's seen from the earth, and it's said that there is a fixed star where you say that "HD 140283" (common name METOSHERA fixed star) is oldest at the universe in the location from which it's about 190 light-years away in the direction of Libra. This fixed star was the oldest fixed star for the moment, and birth was regarded as 16,000,000,000 years ago. But birth is about 13,800,000,000 years before, so the universe doesn't pay any more. It's said that it was about 14,500,000,000 years before (error for plus minus 800,000,000 years) as a result of so redoing calculation. I don't know what kind of calculation is being done, but when including an error, it's logical. So is it only I to think it's a little compulsory?
