Constellation variable of Cepheus

Cepheus has a very famous variable star called Cepheid I, which is contracting and expanding with a period of 5.37 days! The brightness changes accordingly, so it is a typical high brightness pulsating variable star. More than 600 variable stars like this have been found now, collectively known as Cepheid variable stars.

Cepheid 1 is the fourth star of Cepheus, located at the tip of Cepheus. It's white at its brightest,

The darkest time is yellow. Cepheid-1 is 30 times larger in diameter than the sun, but only six-tenths as dense as the sun. In the process of each expansion and contraction, the diameter difference between the front and rear is 5 million kilometers.

There are many variable stars in Cepheus, the most striking of which is Delta, which was called Cepheid No.1 in ancient China (in ancient China legend, Zhao Fu was a good driver of a carriage). It is also a variable star, which was first discovered in 1784.

Cepheid-1' s dimming period is very accurate, which is 5 days, 8 hours, 46 minutes and 39 seconds, 3.5m at the brightest and 4.4m at the darkest, and it is a typical pulsating variable star. It is also a variable star, which was first discovered in 1784. Hot hydrogen clouds are mixed with dark dust belts, because there is a violent star formation area about 2000 light years away from Cepheus. In these and some similar emission clouds, high-energy ultraviolet light emitted by hot young planets hits the surrounding hydrogen atoms. When these electrons recombine with atoms, they will emit longer wavelength light, which can obviously be found on bright spectral lines. In some visible wavelength ranges, the strongest emission line is the red part of the spectrum, also known as H-alpha.

On the night of February 2, 2008, Comet Chen Gao was discovered together with Happy. That is, the magnificent emission nebula IC 1396 discovered by Cepheus has bright clouds and dark dust clouds at the same time. This star birth area, which is 3000 light years away from us, stretches for hundreds of light years, covering more than three degrees of the earth's sky. Short-period pulsating variable stars, with periods ranging from 2 to 6 hours, are also called dog variable stars. Many Cepheus variables have two slightly different periods. The curve of light variation is often close to sine, and the phase is 90 behind the apparent velocity curve, which shows that the maximum and minimum values of luminosity correspond to the minimum and maximum values of radius respectively. The spectral type is roughly between B0 and B2, and the color changes slightly with luminosity. When the luminosity is maximum, the Herold diagram of luminosity variable star is above the main sequence.

Many Cepheus-type variables are sub-stars close to binary or multi-stars, such as arcturus and Antares. Cepheus itself has at least three companion stars.