What is stars? How many types of Stars are there? Let's see!!
The Stars
 |
| Stars |
Stars are the bodies of hot, glowing gas that are born in nebulae. They vary enormously in size, mass, and temperature: diameters range from about 450 times smaller to over 1,000 times bigger than that of the sun; masses range from about a twentieth to over 50 solar masses; and surfaces temperatures range from about 3,000°C to over 50,000°C. The colour of a star is determined by it's temperature,the hottest stars are blue and the coolest are red. The sun, with a surface temperature of 5,500°C, is between these extremes and appears yellow. The energy emitted by a shining star is usually produced by nuclear fusion in the star's core. The brightness of a star is measured in magnitudes- the brighter the star, the lower it's magnitude. There are two types of magnitudes: apparent magnitude, which is the brightness seen from Earth, and absolute magnitude, which is the brightness that would be seen from a standard distance of 10 parsecs (32.6 light years). The light emitted by a star may be split to form a spectrum containing a series of dark lines ( absorption lines). The patterns of lines indicate the presence of particular chemical elements, enabling astronomers to reduce the composition of the star's atmosphere. The magnitude and spectral type(colour) of stars may be plotted on a graph called a Hertzsprung- Russell diagram, which shows that stars tend to fall into several well-defined groups. The principal groups are main sequence stars(those which are fusing hydrogen to form helium), giants, supergiants, and white dwarfs.
Small stars
 |
| Small stars |
Small stars have a mass of upto about one and a half times that of the sun. They begin to form when a region of higher density in a nebulae condenses into a huge globule of gas and dust that contracts under its own gravity. Within a globule, regions of condensing matter heat up and begin to glow, forming protostars. If a protostars contains enough matter, the central temperature reaches about 8 million°C. At this Temperature, nuclear reactions in which hydrogen fuses to form helium can start. This process releases energy,w prevents the star from contracting further and also causes it to shine; it is now a main sequence star.
Massive stars
 |
| Massive stars |
Massive stars have a mass at least three times that of the sun, and some stars are as massive as about 50 suns. A massive star evolves in a similar way to a small star until it reaches the main sequence stage. During it's life as a main sequence star, it shines steadily until the hydrogen in its core has fused to form helium. This process takes billions of years in a small stars, but only millions of years in a massive star. If the surviving core is between about one and a half and three solar masses, it contracts to become a tiny, dense neutron star. If the core is greater than three solar masses, it contracts to become a black hole.
Neutron stars
 |
| Neutron stars |
Neutron stars form from the stellar cores that remain after stars have exploded as supernovae. If the remaining core is between about one and a half and three solar masses, it contracts to form a neutron star. Neutron stars are typically only about 10 kilometers in diameter and consist almost entirely of subatomic particles called neutrons. Neutron stars are observed as pulsars, so called because they rotate rapidly and emit two beams of radio waves, which sweep across the sky and are detected as short pulsars.
||Thanks for reading||
Follow us to get more information about space, science, technology and etc.
0 Comments
Comment us if any problem is there from this article..