“The Stars in the sky without Light Pollution”

Stars are bodies formed by a gaseous structure that leads to nuclear fusion reactions, responsible for energy emission. The Sun is the closest star to the Earth.

Stars are formed by gases and dust that have suffered gravitational collapse inside nebulae.

“Stars form in nebulae and can have a lifetime of millions to billions of years, which varies depending on their mass. It is difficult to estimate how many stars there are today in our Universe, but some astronomers indicate that the number exceeds the 20 digits.”

“The process of formation of the stars that make up our Universe begins in clouds composed of dust and gases called nebulae. The interior of nebulae consists of an environment of high turbulence, caused by the movement of gases and other materials that compose them, giving rise to globular knots, which can undergo gravitational collapse, the initial phase of the formation of a star.In this way, several of these structures are formed inside nebulae, which is why they are called star nurseries.

A star in the first stage of its formation process is called a protostar. The gravitational contraction characteristic of this initial phase continues for millions of years, which promotes an increase in temperature in the core of the protostars and gradually attracts a greater quantity of gases and dust to its surroundings.

It is only after a long period of time that nuclear fusion reactions begin to take place in the central region of stars, when the temperature in this region has already reached at least 15 million degrees Celsius. From then on, the gravitational collapse ceases and there is a situation of equilibrium, beginning a new phase of their lives. The Sun, for example, the only star that makes up the Solar System, took 50 million years from its protostar phase to its mature phase.”

“Types of Stars”

1- “White dwarfs: they are derived from the collapse process of other main sequence stars, consisting of their final stage. Despite emitting brightness, there are no fusion reactions taking place in their core.

2 – Yellow dwarfs: present activity in their core, in which nuclear fusion reactions occur. They are part of the main sequence. An example is the Sun.

3 – Red dwarfs: they are the most present in the Universe. They have small mass, weak brightness and temperatures lower than the Sun.

4 – Red giants: these are stars in an advanced stage of their life cycle, larger in size, but with reduced mass, with less brightness than in the previous phase. In approximately five billion years, the Sun will become a red giant.

5 – Blue giants and supergiants: they are very massive and bright, presenting extremely high temperatures, varying between 10,000 K and 50,000 K, in the case of supergiants. These can be up to 25 times the mass of the Sun. Due to the intense activity that occurs in their core, they are also very young stars with a short life cycle.”

Work done by EBIAH students using internet research.

https://brasilescola.uol.com.br/geografia/estrelas.htm#Resumo+sobre+estrelas

Escola Básica Integra de Angra do Heroísmo

students name: António and Durval