If you're ever in a field, you'll notice how beautiful the sky looks. It has many bright little lights, but they're more than that. Discover all the information about stars here. We'll teach you what they are, what their characteristics are, their types, and much more.
What is a star?
The star is a bright body whose internal constitution is quite similar to the gaseous state of bodies. Because of their gravity, they are able to maintain their state and configuration.
It is said that it is the Sun, the star that is closest to planet Earth. However, the rest of these luminous bodies can only be appreciated without difficulty from the ground, at night.
But not all stars can be seen so easily by the human eye. A large part of these celestial bodies, which can include those that are more distant from the galaxy to the earth, the solar system or the milky way, cannot be observed without specialized equipment.
Some of these stars are so distant that it is impossible to see them from Earth, even using advanced technology telescopes.
The characteristic brightness of stars at night is due to the absorption and release of energy within their core. Through a physical process, the body's hydrogen is transformed into a noble gas, in this case Helium.
Through this physical reaction, the energy that is generated passes from the interior of the nucleus, propagating in the form of electromagnetic waves throughout outer space.
But all this has become quite interesting and it is valid that the following question be asked: how long does a star last? Although it seems complicated, scientists managed to determine exactly how long each of the stars, discovered so far, has.
life of a star
During the period of star formation and extinction, small nuclear reactions are generated, which are responsible for the lifetime of the celestial body until its explosion. It is very normal, that close to disappearing the star, inside it contains a large amount of debris, due to the effects of the transformation.
Scientists manage to establish the amount of matter they contain, the life time and the amount of elements other than Helium and of greater weight. Simply by registering its movement through space, in addition to its brightness and range of its light.
Another peculiarity of the stars is that throughout their lives, increases in their diameter and changes in their Temperature and humidity. It is important to know that the environment where they are located will be factors that can affect their route and rotation.
From the collapse of the gravity of the interstellar regions, which are made up of Hydrogen, Helium and other heavier elements, the life cycle of the stars begins. Through mergers, which release energy in the process.
Thanks to all these reactions, the debris generated inside the star transfers energy away from its center through the heat transfer produced by electromagnetic transfer and fluid movement.
The pressure inside the star prevents it from collapsing. When the hydrogen reserves in its core begin to run out, the star begins to increase in diameter.
Produced this disproportionate increase in its size, the star is transformed, allowing the expulsion of much of the matter, which allows the formation of new stars. All its mass is gradually extinguished, until it becomes a black hole.
Stars and an orbit
When two or more stars share the same orbit, we speak of multi-stellar systems. Which are intertwined in the same gravitational orbit.
If the orbital area they share is very close, their evolution will be more significant, thanks to their exchange of gravity. The grouping of this type of stars are responsible for seeing stellar accumulations or galaxies.
history of the stars
Since time immemorial, the stars have been a valuable tool for all civilizations. They have been an inseparable part of religious culture, invaluable to navigators, as they were used to navigate.
For a long time, they believed that these tiny elements of space remained static in the same place and without undergoing any modification.
Many students of the cosmos, for convenience, gathered the stars in celestial regions, which were used for the purpose of recording the movements of the planets, according to the location of the Sun.
Also, they were able to use the displacement of the Sun, contrasted in a horizontal plane of the stars, to design calendars. That they could be of great help, to program all the activities related to agricultural practices, such as planting, fertilization and soil preparation.
The calendars that are currently known are based on the solar calendar, which uses the axis of rotation and the angle of the Earth movements, in relation to its star, the Sun.
Chart and star list
A star or star chart is a map where the locations are found, of each of them on the spatial plane.
This star map, known to be the oldest, corresponds to the Egyptian civilization and its notable scholars, around the year 1534 BC. Then the geniuses of Babylonian astronomy, were in charge of cataloging and grouping them, between the years 1500 to 1100 before Christ.
The Greeks, for their part, coin that their first list of stars was drawn up in the year 300 BC. C by the astronomer Aristilus. The star index, which was recorded in the XNUMXnd century B.C. C, is due to the astronomer and mathematician Hipparchus of Nicaea. Hipparchus is also known as the one who discovered the first nova or new star.
Hipparchus's map incorporated a total of approximately 1000 new stars. They were used to complete the compilation that the geographer and astronomer Claudius Ptolemy was carrying out.
The geniuses of Chinese astronomy harbored the hope that new stars would be produced, even though they were aware of the rigidity of the changes in the celestial space.
The possibility of some changes was rewarded when after almost 190 years, after the age of Christ, they were able to observe, describe and record a supernova or super star. Currently, this super star is registered as SN 185.
Star discoveries continued to be recorded. Next on the list was the supernova SN 1006, sighted and recorded by the Egyptian-born astronomer Ali Ibn Ridwan, in collaboration with other Chinese astronomers in the year 1006 AD.
The current Crab Nebula is thanks to the discovery of the super star SN 1054. It was sighted by a multidisciplinary group of Chinese and Arabs.
Inventions and names
Astronomy and everything associated with it owe much to the Arab astronomers of the Middle Ages. They were in charge of registering and naming a large number of stars and invented many measuring instruments, which were very useful for calculating the positions of the stars.
The Arab astronomers were also the ideologues and visionaries who dedicated part of their scientific knowledge to the establishment of research institutes and large star observatories.
The history of astronomy has invaluable publications and renowned scientists who dedicated much of their lives to the advancement of science and knowledge of the stars and planets.
Some of them are mentioned below:
- Abd Al-Rahman Al Sufi, Persian astronomer. Author of the book The Fixed Stars, in 964 AD.
In the post, he lets us know about his observation of the star grouping: Omicron Velorum and the Brocchi set. In addition to the Andromeda galaxy.
Abu Rayhan Biruni, was a Persian astronomer, who was able to describe the grouping of stars and celestial bodies called the Milky Way. In his notes, he describes it as a set of pieces, which had elements similar to that of a star. Abu Rayhan Biruni, is also credited with pinpointing the distance of certain stars during a lunar eclipse in AD 1019.
The Milky Way and other formations
According to the astronomer Ibn Bajjah, in 1106 AD, he stated that the Milky Way was made up of numerous stars. Which rubbed against each other, giving the feeling that it was a continuous figure, product of the change in speed and direction of the waves.
Several discoveries were made possible by European astronomers. Among which Tycho Brahe stands out, who was able to identify the novas in the sky, during the night. Affirming with this, that the heavens, if they underwent changes.
Giordano Bruno in the fifteenth century, proposed that these celestial bodies would most likely have other planets, rotating in their orbit. Possibly as it happens with the solar system. Theory that was initially proposed by Epicurus and also in the atomic theory of Democritus.
Unifying criteria
Already in the XNUMXth century, the criteria around the definitions and classifications of the celestial bodies began to be unified. They established the reasons why these bodies did not exert any pressure on the solar system.
Physicist Isaac Newton and theologian Richard Bentley agreed on the idea that stars were distributed evenly throughout space.
In the XNUMXth century, the first measurements of the movement of two celestial bodies that had changed their location, recorded by Hipparchus and Ptlomeus, were carried out. This fact was thanks to Geminiano Montanari, an astronomer who observed variations in the star Algol, from the Perseus constellation.
Well into the eighteenth century, the first measurements could be made for the distribution of celestial bodies in the sky. Task that was in charge of the astronomer William Herschel. Through some indicators, placed in a whole strip of vision.
Radiation analysis
Joseph von Fraunhofer in collaboration with Angelo Secchi, began a study where they made comparisons of different photons from a large number of celestial bodies. They were able to determine that there are disparities in the intensity and absorption of the spectrum.
From the record of these events, stars began to be classified according to the types of photons. This classification was later improved by two astronomers.
In the year 1865 Secchi began to classify the stars by spectral types. However, the modern version of the stellar classification scheme was developed by the American astronomer Annie Cannon.
Bessel Friedrich is responsible for making the first measurements of the distance between stars. In addition, this astronomer and mathematician was able to record, through observation, changes in the location of the star Sirius.
Stars of the XNUMXth century and the new techniques
With the arrival of the XNUMXth century, a series of technological advances took place, which allowed significant progress in the analysis and observation of celestial bodies.
Another of the factors that played in favor of the recognition of everything that was taking place in the sky, were the advances in the subject of photography. Better camera focusing capabilities could be developed, which allow better images to be obtained.
One of its best exponents was the German physicist and astronomer Karl Schwarzschild. Through him, from this magnificent tool, he deduced that, comparing what he saw in his telescope and what was captured with the camera. The temperature of the star could be determined.
With the incorporation of new, more advanced tools, such as the photoelectric photometer. Higher precision measurements could be made by measuring the distance intervals of the waves.
In the early 1900s, measurements of the size of a star were made for the first time. With the use of an interferometer, which simply consists of an instrument that interferes with light waves.
https://www.youtube.com/watch?v=X2tU_F0fy5o
The XNUMXth century was full of great observations and advances in the knowledge of these celestial bodies. Among those that stand out:
- Physical structure of stars.
- Hertzsprung-Russell diagram, for the incorporation of physics to the study of the stars.
- Development of models to theorize about the interior and evolution of stars.
- Cecilia Payne-Gaposchkin's thesis, where the composition of Hydrogen and Helium is proposed.
The set of photons of the stars, had a significant leap in its understanding, through the advances that occurred in physics and Planck's quantum theory. Being able to know how the stellar atmosphere is chemically constituted.
With the development of new telescopes, stars can be observed more than 100 million light years from planet Earth. Such as the case of, the celestial bodies that are located in the galaxy M100.
Creation of the heavenly bodies
If you concentrate on observing and recording the areas of space where there is greater density, you will notice how the celestial bodies undergo condensation. This phenomenon occurs in the less solid parts of the interior.
These formation zones are called Molecular Clouds, which are composed of one of the elements with the greatest presence in the entire system, such as Hydrogen, in combination with Helium and other elements.
One of the areas of greatest activity in star formation is the area known as the Orion Nebula. Here, millions of these bodies are born, which will later position themselves in different parts of the sky.
There are stars that are within the category of massive celestial bodies, they are nothing more than bodies whose temperatures are very high. This makes it easier for them to brighten nebulae, electrically charge hydrogen molecules, in addition to producing gas and plasma clouds.
But this process of constant formation and exchange of energy is cut off, preventing new stars from being produced.
Stars typically spend much of their lives in the main sequence state. That is, they are located according to the emission of light and the temperature of their bodies.
Classification according to mass
The stars, according to their mass, have different characteristics as they develop. Stars that have a mass ten times greater than that of the sun (10MS), have a totally different end than those with less mass.
According to these aspects in relation to their mass, they are classified as follows:
with very low mass
They are bodies, which have a mass less than 1 solar mass (MS). They have the ability to transfer heat and distribute helium evenly throughout the celestial body.
For this reason, their cover is not burned and they do not transform into red giant stars. On the contrary, they lose their ability to merge and become dwarf stars due to the loss of their core energy.
These stars usually have a longer life than the rest of the celestial bodies that are transformed in the universe. Therefore, it is quite difficult to determine their age, since none of them have reached the level of white dwarfs.
low mass
Those celestial bodies, whose masses range between 0,5 and 2,5 solar masses (MS) and according to their constitution, can become the so-called red giants or stars that have been running out of fuel from the core.
These stars are made up of an interior of carbon and oxygen, which later consumes the Hydrogen in the core. This causes the entire body to contract, while its temperature rises, causing its outer layers to cool.
with intermediate mass
The stars of this group have a mass ranging from 2 to 10 solar masses (MS) and their evolutionary process is very similar to that of low-mass stars.
These celestial bodies, have periods of transformations in which the combustion of Helium occurs, to later form a center of carbon and oxygen of various levels.
massive stars
Frequently, they are stars whose solar mass is between 7 and 10 solar masses. Once their core fuel is consumed, they transform into supergiant stars, fusing all elements heavier than helium.
Its lifetime is related to the collapse of its interior, until an explosion occurs that gives rise to Supernovae.
Stars and their formation
These interesting formations that can be seen in the sky, begin their development with a fluctuation in gravity, within the molecular clouds. All this thanks to the pressures generated by the collisions between galaxies.
Once the gravitational layers reach the top of their density, they make it possible for everything necessary to be delivered to create an instability. Then, at that precise moment, a collapse occurs, due to the action of the force of gravity.
Inside the cloud, everything begins to collapse and all the gas fragments give rise to a thick and dark cloud, called Bok globule. Once the imbalance has occurred, the energy is transformed into heat, increasing the temperature.
At the moment that the cloud begins to find gravitational balance again, a new star is born in its core.
Stars that are just in the process of formation are surrounded by discs, which are maintained by the exchange of gravitational energy. The period of reduction or nuclear fusion can take approximately fifteen million years.
The newest celestial bodies, that is, those whose solar mass does not exceed 2 MS, are called T Tauri and they are the new stars, of greater visibility.
The star has just formed, it expels gases that are responsible for reducing the rotational movement of the dying star. The combination of these gases with light waves causes the surrounding cloud to move away from its orbit.
It is common that the stars that have just formed, while they are at the same temperature, their brightness is considerably opaque. Being this, a characteristic of the environment where each of the stars were formed.
The sequences and order in the formation of stars are mentioned below.
Main order of formation
These plasma spheres spend almost their entire life liquefying Hydrogen into Helium, at high temperatures and gigantic pressures around their center. The stars that are located in this first level are also known as dwarf stars.
When the count begins in the life of a star, which starts from age zero, the concentration of Helium gas will increase in its center. For the same reason, an increase in its temperature and light is also noted.
In the case of the Sun, since its birth more than 4000 billion years ago, its luminosity has increased by almost 50%, since it entered the first phase of formation.
Product of the constant transformations, each one of the plasma spheres that are formed, generate the stellar breezes, which are responsible for transporting the gases towards space.
Due to its constant transformation, for example, the Sun releases each year of its mass, on average more than 10 MS, substantially affecting its development.
The period that a star uses during its passage through the main formation sequence will depend on the amount of energy reserves it has and the speed with which it mixes its elements.
As massive plasma spheres burn energy faster, their lifetime will be shorter. On the contrary, those of low mass use their energy more slowly, which lengthens their life.
The coordination between a minimum energy expenditure and the constant supply of fuel allows the life of low-mass celestial bodies to be much longer.
In this phase of development, the so-called red dwarf stars suffer an increase in their temperature and radiation, due to the retention of Helium. But due to the loss of their Hydrogen reserves, they undergo a contraction that makes them become other luminous spheres of plasma, that are the stars white dwarfs, which have already suffered a drop in temperature.
heavy elements
As you well know, mass plays a major role in the evolution of a star. But those elements whose weight is greater than Helium must also be considered.
Scientists have a way of classifying elements whose weights are above Helium. The grouping of all these elements inside the star is called metallicity.
To understand what this term is about, it is necessary to mention that the metallicity of a celestial body directly influences the period it takes to use its energy.
The magnetic field of stars is also influenced by metallicity. In addition to the affectation that it causes to the intensity of the stellar breeze.
Molecular clouds have a lower concentration of metallicity, in those stars of greater antiquity and thanks to the constant transformations undergone. As stars expire and die, they serve as fertilizer for these clouds.
main post sequence
Once the stars, whose masses are less than 1 MS and having exhausted all their Hydrogen reserves in the nucleus, they begin to mix Hydrogen, in an area external to the Helium nucleus.
In parallel to this fuel consumption, which occurs in the core at the outer levels, an expansion occurs. This generates a cooling, which then ends up becoming a red giant star.
When approximately 5000 million years have elapsed and the Sun passes into the Helium combustion phase, the King Star will undergo an enlargement in its radius of more than 100 million kilometers, losing a third of its current mass.
This characteristic of the Sun's transformation is due to the burning of hydrogen levels and therefore more helium production, which generates an increase in temperature and mass.
massive stars
In this formation phase, as in other stages, an important use of Helium is produced, in order to move on to the next level of transformation. The stars end their state of blue supergiant plasma, to become another, but this time red.
Another of the particularities that these stars have, in addition to being extremely hot at their core and losing significant mass, is that they can evolve into another star, whose gas and particle emissions have greater weight than Hydrogen.
The formation and transformation process depletes the helium reserves contained in the nucleus. This is reduced, causing the pressure and temperature to increase, to the point of mixing the carbon present with silicon, neon and oxygen.
It is known that the star is in its final stage, when in each of its layers there is an increase in the production of iron. A fusion in the Iron nuclei does not generate an expulsion of energy and consequently, there will be no further transformation.
Destruction
Due to the shrinking of the core of the star, the energy emissions are intensified. This phenomenon causes that, due to the effect of the pressure exerted on its layers, the gases are expelled from its interior, towards the exterior, forming a nebula.
Once the expulsion of gases and particles ceases, a stellar mass remains. If this mass is below 2 MS, it is said that a white dwarf star is formed. These do not have enough surface to generate new formations.
After this period of release of energy and gases, the sphere that is no longer plasma, becomes a black dwarf and it will be in this state, where it will remain for a long time.
In successive collapses of this stellar mass, several explosions are triggered, until reaching total collapse, becoming a supernova.
Characteristics of celestial bodies
The main characteristics of a luminous sphere of plasma are the life time, how they are constituted, their size, the amount of light they radiate, among others. Each one of them is mentioned below.
Time of life
A large part of these luminous stars have ages that range between 0 and more than 10.000 million years. Very few stars have ages that exceed 13.000 billion years.
The celestial body discovered to date, and which by all accounts is the oldest, was cataloged as HD 140283. It was also given a colloquial name, Methuselah, and is estimated to be more than 14.000 billion years old.
While the star, according to its transformation process, is more massive, its life becomes shorter. This, thanks to the forces to which their nuclei are subjected, which also causes the consumption of Hydrogen to be greater.
Red dwarf stars, whose mass is very small, consume hydrogen much more slowly. Which allows to prolong its life, millions of years more.
chemical constitution
The general constitution of the celestial bodies revolves around the combination of Hydrogen, Helium and small amounts of other heavier elements. That in general, are portions of Iron present in the atmosphere of the star.
The presence of iron ore, which can be found in the atmosphere, is an indication that this star most likely contains a planetary system. Therefore, we invite you to read our article on numbers of stars.
The stars that were recorded with the greatest amount of Iron are: Leonis and Hercules. While those of lower concentration, HE 1327-2326 stands out.
Diameter
Due to its location so distant from planet Earth, all the stars can be seen in the sky as twinkling points, but this is not the case with the Sun, which is also a star. Because it is much closer to Earth, it can be seen more easily.
The Sun has the largest equatorial diameter of all celestial bodies. The diameters of other stars are quite small. They can only be observed from Earth with telescopes that use interferometric technology to capture them.
Also, it is usual to use the occultation technique to make measurements of the diameters of the stars. This consists of measuring the loss of luminosity of the celestial bodies, while the Moon hides them.
These stars can measure up to 40 kilometers in diameter, as in the case of neutron stars and also those that have a diameter greater than 1.000.000 kilometers, such as those found in the constellation of Orion.
Movement
The stars have two types of movements. These are radial velocity motion and transverse angular motion.
Using the radial velocity, it is possible to calculate the displacement of the star. From a given point of observation, to the farthest point of the record.
While proper or angular motion allows us to pinpoint changes in the position of stars in the sky, these types of celestial bodies are most likely located closer to the Sun.
According to scientific studies, it is known that younger bodies tend to have slower speeds than older ones.
Magnetic field
This force is produced inside the star. The movement of the magnetic field works as a kind of dynamo, where the movements generated by the electric charges provoke the magnetic fields of the celestial body.
Each star has a very specific field intensity. The intensity depends on the mass and chemical structure of each star, as well as its rotational speed.
Plasma spheres that are younger tend to rotate at a higher speed, consequently their surface activity is high, as a result of the magnetic field. The opposite is true for older stars, which have lower surface activity.
Mass
The stars whose formation stages are at the massive level, have a lifetime of a few million years. The observations made indicate that the limits of the masses of the star with the highest density are located at more than 150 MS.
Other theories assume that before the big bang of the universe, the stars had a mass greater than 300 MS. This thanks to the absence of the lithium element in its internal constitution.
Having a mass of more than 70 times the size of the planet Jupiter, the 2 MASS star is one of the smallest stars in the constellation and in which a fusion occurs in its core.
The grouping of the mass and the radius of a celestial body, establish the gravity on the surface of it. Thus, the luminous giant plasma spheres have a lower surface gravity than those found on the main sequence.
This gravity that occurs on the surface influences the light waves, which are generated by the amplitude of the absorption lines.
Rotation
Using a piece of equipment for measuring the electromagnetic spectrum, called a spectroscope, they were able to determine the rate of rotation of stars. Specifying that the young stars perform this movement at more than one hundred kilometers per second.
For example, the Star King, performs the rotation movement, approximately every 30 days, this will be according to the latitude at which it is located. The magnetic field and the stellar breeze directly affect the speed of rotation of the stars.
Those celestial masses that entered a period of exhaustion, due to the loss of their mass, tend to increase their speed of rotation. But its average, compared to the rest, is very low, because the stellar winds counteract said speed.
Temperature
In celestial bodies, temperature is closely related to their ability to produce enough energy inside and their size.
In general terms, the temperature is linked to the ability of that star to expel the same amount of electromagnetic radiation, according to the size of the stellar surface. Inside, they can reach millions of degrees Kelvin.
As one of the conditions for the classification of stars, their temperature is used. And this can be determined by its ability to absorb light waves and the speed of transformation of certain elements inside it.
Luminous plasma spheres, which have a larger surface area, can reach temperatures in excess of 45.000°K. The Sun, for example, has a temperature above 5000 °K, red giants can have temperatures above 3000 °K.
Stars and their ranking
The Greek astronomer Hipparchus was the first to classify the stars. Which was continued by Ptolemy and recorded in the work Almagest. This classification was based on the power of the light seen from the ground.
Levels of descending brightness magnitudes were established for their classification. Thus it was that the stars with the greatest power of light were located on the scale of one or first magnitude. This positioning, was contradicting, according to the decrease in brightness, which were the stars of magnitude 6.
In the present, the classification system developed at the beginning of the 20th century is used and whose levels go from the letter A to Q. For this rearrangement in the classification of stars, the line of electromagnetic radiation of Hydrogen and the core temperature were considered.
Other aspects are also considered for its classification, such as, for example, the incidence of luminosity in the spectrum. Which can be emission or absorption, being directly proportional to size and gravity.
Another of the characteristics used for the classification of celestial bodies is the addition of numbers that allow recognizing the size of each one of them.
So, for example, the number 0 corresponds to hypergiant stars and a III will be to identify, what are giant stars. This sequence would reach number VII, corresponding to white dwarf stars.
Let's look at the following example of the Sun, which is a G2V-type star. The following can be deduced from this nomenclature:
- It is considered to be a dwarf celestial body (G)
- The sun is located among the hottest stars (2)
- It is a luminosity five main sequence star (V)
Other nomenclatures
In order to be able to add more descriptive details to each of the stars, astronomers devised a fairly complete system. This consists of adding lowercase letters to the end of the spectral type.
The purpose of this system is to be able to add more recognition features. Such is the case of a e it will indicate that you are in the presence of an emission line; while one m it is indicative of high concentrations of metals.
Another peculiarity in the stellar classification is the use of vowels and consonants in capital letters. Dwarf plasma spheres have their own identification and it starts with the letter D, is in turn has its classes that are A, B, C, O, Z y Q, followed by a digit indicating its temperature.
Classification by spectrum
This classification takes into consideration the spectrum of each star. However, this is not so decisive to differentiate one from the other. Since there may be celestial bodies whose temperatures are identical, but not have the same size. This directly affects its brightness.
The last stellar classification record showed that white dwarf stars make up 10% of the total. Three-thirds of the heavenly bodies are of type M, the types K y G they agglutinate 14% of them. While stars with higher mass, such as A y Ftheir number is very small.
according to its severity
The luminous plasma spheres, according to their gravity, can be classified, considering four gravitational principles, validated by the International Astronomical Union (UAI). And which are mentioned below:
stellar gravitational center
To place a celestial body in this category, it is necessary to establish whether or not it has a stellar center. That is, if that star in question is part of a system.
Those stars that belong to a stellar center of gravity are called systemic celestial bodies and those that are outside a stellar system are called solitary.
Systemic stars according to position
In this category, all those stars that belong to a stellar system and that, in turn, have a subdivision are grouped, namely:
- Central: are those that have the function of acting as centers of gravity for other stars.
- Satellites: they are grouped in this subdivision, to the celestial bodies, which describe a Orbit, around another central star.
By gravitational group
Here are the stars that are grouped, depending on whether they attract each other, according to their gravitational force. This classification has two subdivisions that include cluster and independent stars.
Among the most outstanding characteristics of this type of celestial bodies, is the ability they have to join or repel each other. Another particularity of the stars grouped in this category is that, despite having a center of gravity, none of them rotate around the others, even though they are gravitationally linked.
Following are the characteristics of cluster and independent stars:
- Cumulative
These are capable of forming stellar clouds. When the cloud or cluster is of the globular type, they will be attracted by the gravity of each one of them. But if the cloud or heap is open type, a gravity attraction phenomenon will occur, but this time the gravitational center originates from the center of mass of the cloud.
- Independents
These types of stars do not get along very well with the rest of their peers. They are not capable of forming stellar clouds with other celestial bodies. But independent stars can be observed, forming part of a system, since they revolve around other stars or act as a center of gravity for their peers.
Planetary system
In this group, are the luminous spheres of plasma, which belong together with other stars to a planetary system. It is important to be clear that a system of planets is the grouping of that celestial body and the rest of the planets, comets and asteroids, that revolve around it.
All-Star Association and Organization
The particularity that stars have is that they are not scattered in a disorderly manner throughout the universe. They tend to cluster together, generally in galaxies in the company of interstellar gas and dust.
multistar system
It is called multistellar system, to the group that can exist between two or more stars, which are united by the force of gravity that unites their orbits. For reasons of orbital adequacy, the systems that group infinity of stars, tend to be grouped by hierarchical levels of the stars.
It is very common to find groups with a greater number of stars, which are called clusters or star clouds. These can be between loose star junctions, to huge amounts of Clouds globular.
The planet Earth has a very close proximity, in addition to the Sun, with the red dwarf star Alpha Centauri, approximately 40 billion kilometers away.
Collisions between stars are very rare, due to the distances between them, outside the galactic nucleus. Further inside the nucleus, in the globular clusters, collisions between celestial bodies are more frequent.
bound stars
The gravitational unions between the stars, generate systems between two, three or groups of a greater number of stars. A high percentage of the Milky Way's disk is made up of binary stars.
Another percentage of celestial bodies, are grouped in greater numbers, causing star clusters. These are produced by changes in the gravity field of the galaxy. They are also due to the formation of starbursts.
Two types of star clusters can be found in the galaxy, these are:
- globular clusters
These are the oldest formations and are found in the rings, having millions of stars in their grouping.
- open cumulus
They were recently formed, unlike the globular ones, they are located in the disk and the group of stars is smaller.
isolated stars
It is very likely to observe stars that cannot maintain stable bonds with each other. Many of them, in the same way as the Sun, make their trips without company, they react only to the magnetic field established in the galaxy.
star organization
Generally, the plasma spheres are not distributed in a regular way throughout the universe. They are grouped in quite numerous groups called galaxies.
The most recognized is the Milky Way, in which millions of stars gather, many of them in a very small plane of the galaxy. With the naked eye and at night, the sky can be very thick with stars. But it will only be an optical illusion, of the plane that is observed in the galaxy.
Using the stars to navigate
Between the celestial bodies, there are exorbitant distances. But viewed from Earth, these distances and positions may indicate a fixed position. Due to the precision of their position on the map, they are used to guide the course of navigation.
Ancient sailors used the stars as the only means to locate themselves when they were at sea, until they reached the mainland. With the development and technological research, this positioning system was left in disuse.
Radiation
All the energy that is generated, thanks to nuclear fusion, is spread throughout space, in the form of electromagnetic radiation and particle radiation.
The particle radiation generated by a star is revealed as a stellar breeze. These circulate from the outer layers, with electrical charges and alpha and beta type particles.
All the energy that is generated in the nucleus is responsible for the stars being illuminated. This phenomenon is produced by the fusion that originates between the nuclei, forming a single nucleus of heavier elements.
This fusion process produces the expulsion of electromagnetic radiation particles, which are transformed into visible light when they reach the outside of the stars.
Color is determined by the most intense light frequency. That depends on what temperature exists in the outer layers of the celestial body. Additionally, in light that can be seen, there are other forms of electromagnetic radiation, imperceptible to the human eye.
Bright
The brightness, or luminosity, of a star refers to the magnitude of light and different forms of energy that is radiated. This is directly proportional to the radius and temperature of the star.
The star spots are the reflection of the presence of low temperatures of that celestial body. Thus, small and dwarf stars have star spots, without distinctive features.
In the case of giant stars, larger spots can be observed with characteristics that allow them to be distinguished more easily. They can be seen, a dark part in the stellar limb, which causes its luminosity to decrease.
Size
The luminosity of a celestial body is related to its size. It also influences the distance it is from Earth and the number of obstacles that light encounters, while passing through the Earth's atmosphere.
The intensity of the brightness depends on the size of the star, the larger the size the intensity of the star will be less. Contrary to the case of stars of low mass, these will have a more intense brightness.
star structure
Inside a celestial body, which is stable. All the forces that are exerted on any volume are balanced equally. These forces in balance are the gravitational force that acts towards its interior and another force that exerts pressure towards the outside, due to a difference in pressure, on the star.
The variations of the pressures originate from the changes in temperature that are generated in the exterior and the core of the celestial body. The temperature at the center of a giant star can hover around more than 100°K.
Both the temperature and the pressure, resulting from the process of consuming Hydrogen by a celestial body, are so high that they make it possible to generate nuclear fusion. Fusion that produces such an amount of energy, ideal to keep the star stable.
The fusion
Once the fusion process begins in the nucleus, it releases energy in the form of gamma rays. These light-energy particles interact with the gases around the nucleus, adding heat energy to it.
Celestial bodies transform Hydrogen into Helium. This phenomenon slowly contributes an amount of Helium to the nucleus. Until you have completed all the levels, whereupon power generation in the core is paralyzed.
star balance
Inside a star, not only nuclear fusions are generated. There is also a balance of gases and liquids, which are responsible for maintaining the balance of thermal energy.
Product of all the processes of internal transformations, they cause variations in the temperatures that are expelled to the outside. The flow of that energy leaves empty spaces, which are gradually filled by the flow of incoming energy.
The emission area is the inner zone of the star; the energy transfer to the outer part must be assisted by heat transfer between layers, for the simple reason that the heat transfer system by mass movement is nonexistent in this area.
the photosphere
The photosphere is the part of a star that can be seen, without the need for specialized equipment. In this zone, the gases present in the star become transparent, in the presence of light energy, to later be expelled to the outside.
In this area, it is where the stellar spots originate, which are those areas that have a temperature much lower than the average of the rest of the star.
Above the photosphere is the stellar atmosphere. If you are looking at a main sequence celestial body, such as the Sun. Below the atmosphere is the chromosphere, which is a fairly thin region. There, large concentrations of gas flow and release of magnetic radiation are formed.
Corona
Approximately a few hundred kilometers away from the chromosphere is the corona. This area is composed of a large amount of gases, at high temperatures and that extends millions of kilometers, since its formation in the chromosphere.
Contrary to the high temperatures of the corona, its luminosity is very poor, due to the low densities of the gases that make it up. For example, the Sun's corona is visible only and exclusively during a solar eclipse.
Heliosphere
This region is made up of stellar winds generated from the corona. They move outward until they make contact with the surrounding matter.