Although they look the same when observed with the naked eye, there are significant differences between the different types of stars in space. For example, the brown dwarfs and the red giants have very different attributes.
When we look up at the night sky, we can see thousands of bright dots that we affectionately call stars. However, not everything that shines in the sky is actually a star, or corresponds to the classic type of star that people imagine.
The most important characteristics for differentiating star types include the color and the brightness they emit . Although these attributes can be seen with the naked eye in some brighter, nearby stars, detailed observation requires the use of specialized instruments, computer models, and other space-based methods.
Current technology already allows scientists and enthusiasts to use online tools to study stars that are thousands of light years away. Earth . However, the discovery of new stars, especially more distant ones, still depends on more complex observations with modern space telescopes, such as the James Webb .
Differences between stars, brown dwarfs and red giants
According to NASA (the US space agency), astronomers estimate that there are between 100 billion and 400 billion stars in the universe. Milky Way while the universe may contain up to a septillion stars — a sequence of numbers that contains 24 zeros. But not all of them are the same.
Stars
According to the Encyclopedia Britannica, a star is any massive celestial body that emits light through nuclear fusion within it. Although we see thousands of stars in the night sky, only a small portion of them can be seen with the naked eye.
The others can only be observed with the help of telescopes, both terrestrial and space-based, which collect data on different types of radiation, including visible, infrared, and ultraviolet light.
Small stars burn fuel more slowly and can live for up to trillions of years, while more massive stars can burn out faster and cease to exist in millions of years. To be considered a star, a stellar object must have between 0.08 and 100 times the mass of the Sun.
According to NASA, the birth of stars begins in clouds of gas and dust called molecular clouds (nebulae) . When these clouds collide with each other, they can collapse and release material that forms a protostar. In fact, many stars are born together and form star clusters.
After a few million years, the internal process of intense pressures and temperatures causes the core of the protostar to compress the hydrogen atoms, initiating the process of nuclear fusion to form helium. Thus, a star is born. But there are several stages of a star, such as red giants.
Red giants
In an official publication, Esa (the European Space Agency) explains that a red giant is an advanced phase of a star that was once stable. The birth of this type of celestial body occurs after the star has exhausted the hydrogen in its core; this phase occurs in stars with masses between about 0.8 and 8 solar masses (or 80% to 800% of the mass of the Sun).
Shortly after, the core begins to contract and heat up, and hydrogen fusion begins in a layer around the core. This causes the star to swell and expand by up to hundreds of times. This is why red giants are cool on their surfaces and have a reddish coloration. The Sun is one of the stars that will become a red giant; this is the next stage of its evolution, but it is expected to take about 5 billion years.
Typically, red giants can last up to a billion years, but they are not the final stage of a star. After this stage, a star can turn into a white dwarf.
Brown dwarfs
Brown dwarfs are not exactly considered stars, as they are in the category of substellar objects. In other words, they are celestial bodies that have a mass between that of the smallest stars and that of gas giant planets.
This type of substar can be up to 70 times more massive than planets like the gas giant Jupiter, but they do not have enough mass to sustain hydrogen nuclear fusion and do not emit as brightly as stable stars. They are also often called failed stars, or failed stars, because they do not emit as much brightness.
Their atmospheres are more complex and similar to those of planets, and they are harder to find precisely because their visible light is extremely limited. The first brown dwarf discovered, Gliese 229B was only found in 1995.
This content was originally published in What are the differences between stars, brown dwarfs and red giants? on the CNN Brasil website.
Source: CNN Brasil
Charles Grill is a tech-savvy writer with over 3 years of experience in the field. He writes on a variety of technology-related topics and has a strong focus on the latest advancements in the industry. He is connected with several online news websites and is currently contributing to a technology-focused platform.
