Stars

 

Stars are incandescent and gaseous celestial bodies that are composed of a large amount of gas, mostly hydrogen. The star exudes light and heat that occur in thermonuclear reactions in the center of the star. Their main feature is to radiate light, heat and other forms of radiation. Although most stars exist as an independent, three of the four stars exist as part of a binary system. Some star properties can be concluded from an immediate perception. We refer to the example of the perceived glow of the star as the apparent star or the apparent star Magnitude. The apparent star of the size is determined by the light during the star receiving the Observer.

How are Stars Formed?

The beautiful nebula you’ve probably heard of stimulates the life cycle of stars. It is in them that the new stars are formed. Nebula also gives life to comets, new planets, and satellites.

Supernova explosions are the other way to give birth to new stars. They eject heavy elements into space, thus thickening the gas clouds and forming new stars.

These towers of cosmic dust and gas make up part of the Eagle Nebula. These so-called Pillars of Creation are part of an active star-forming region within the nebula. Credits: NASA, ESA and the Hubble Heritage Team (STScI/AURA)

Types of Stars

Constantly fading stars, which in the process of thermonuclear reactions can not compensate for the lost energy.
Brown dwarfs
Low-mass stars that gradually lose gases from their surface in the form of a stellar wind.
White dwarfs
Stars with relatively low temperature but high luminosity
Red giants
Stars that have changed their brightness at least once.
Variables
Characterized by high temperature and luminosity, unlike other stars, in their wide spectrum, in addition to hydrogen and helium, there are compounds of oxygen, nitrogen and carbon
Wolf Ray stars
Stars that can sometimes blink.
New stars
Can blink more often than "new stars", thus changing its brightness sharply.
Supernova stars
An explosion of a massive star, after depletion of energy and fuel released as a result of thermonuclear reactions.
Hypernova stars

The Smallest and Largest Star Known to Humans In the Universe.

The smallest star is considered to be a star OGLE-TR-122b. It is part of the binary system., that is, knitted with another star through gravity. Perhaps there are smaller stars, just technological progress has not yet reached the level to allow people to see them.

The largest star giant – UY Shield. Its size exceeds the size of the Sun in 1700-2000 times! Agree, it’s hard to even imagine! Now this star is in the final stage of its development.

Why are Stars not Visible During the Day?

The reason for this is the Sun, due to the fact that it is located very close to us from their light so is overshadowing other stars that are much further.

How do Stars Differ from Other Planets?

  • The main feature of stars is their ability to emit light Planets do not possess this property, they can only reflect light.
  • The stars are glowing bodies.
  • The stars are  larger than the planets.
  • The stars are motionless as the planets move in a certain direction.
  • Chemical composition, the composition of the stars includes light gaseous elements. The planets are made up of solid particles

Dimensions, Mass and Luminosity of Stars.

Comparative dimensions of the Sun and the planets of the solar system.

We already know that the Sun is a common, medium star. There are stars much larger than the sun, such as the Sirius star, the brightest star in the night sky. Sirius is 2 times more massive than the Sun and 1.7 times its diameter. It also emits 25 times more light than our daylight!

Another example is a star-shaped inflorescence that heads the constellation Virgo. Its mass is 11 times the size of the Sun, and its luminosity is 13,000 times larger! It is hardly possible to even imagine the powerful appearance of this star!

But most stars in the universe are still smaller than the sun. They are lighter and shine much paleer than our star. Called the most common red dwarf stars, as they emit mainly red light. The typical red dwarf is about 2-3 times lighter than the Sun, 4 or even 5 times less in diameter and 100 times darker than our star.

There are about 700 billion stars in our galaxy. Of these, at least 500 billion will be red dwarfs. But unfortunately all the red dwarfs are so dark that none of them are visible in the sky with the naked eye! To observe them, you need a telescope, or at least binoculars.