Detailed Desription of Stars. What is a Star? , Classification of stars, Hertzsprung-Russel Diagram, Spectral Classes, Luminosity, Variable Stars, Composite Stars, Neutron Stars, Black Holes, Star Clusters, Supernovae, Binary Star, Chandrashekhar Limit, Limit Value Calculation Formulae, Applications of the limit, Tolman-Openheimer Volkoff Limit, About Subrahmanyam Chandrasekhar
'A star is a luminous sphere of plasma held together by its own gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth. Historically, the most prominent stars were grouped into constellations and asterisms, the brightest of which gained proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardised stellar designations. However, most of the stars in the Universe, including all stars outside our galaxy, the Milky Way, are invisible to the naked eye from Earth. Indeed, most are invisible from Earth even through the most powerful telescopes.'
Detailed Desription of Stars. What is a Star? , Classification of stars, Hertzsprung-Russel Diagram, Spectral Classes, Luminosity, Variable Stars, Composite Stars, Neutron Stars, Black Holes, Star Clusters, Supernovae, Binary Star, Chandrashekhar Limit, Limit Value Calculation Formulae, Applications of the limit, Tolman-Openheimer Volkoff Limit, About Subrahmanyam Chandrasekhar
'A star is a luminous sphere of plasma held together by its own gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye from Earth during the night, appearing as a multitude of fixed luminous points in the sky due to their immense distance from Earth. Historically, the most prominent stars were grouped into constellations and asterisms, the brightest of which gained proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardised stellar designations. However, most of the stars in the Universe, including all stars outside our galaxy, the Milky Way, are invisible to the naked eye from Earth. Indeed, most are invisible from Earth even through the most powerful telescopes.'
3. Birth
• Stars are born in the nebula, which are huge
clouds of gas and dust. The nebula begins to
contract under the pull of its own gravity. This
forms a protostar.
4. Protostar
The star begins to take shape. The
temperature continues to rise and nuclear
fusion begins to take place. The pressure from
inside the star finally equalizes the gravity
pushing in, and the star stops contracting.
6. Main Sequence Star
• Stars live out the majority of their lives in a
phase termed as the Main Sequence. This is
the longest, most stable period of a star’s life.
It converts hydrogen to helium in its core,
generating heat and light.
7. Red Giants and Supergiants
• As the nuclear fuel becomes depleted the core
contracts and our layers expand.
8. Sun Size Star
Sun Red Giants Planetary Nebula
White Dwarf Black Dwarf
9. Planetary Nebula
• Now the outer layers of the star start to drift
off into space. The star loses most of its mass
to the nebula.
10. White Dwarf
• The star cools and shrinks. No nuclear
reactions take place and the faint star radiates
it heat into space.
11. Black Dwarf
• The star will eventually lose all its heat and
energy and become dark and cold.
16. Black Hole
• It contracts and becomes a black hole. The
gravitational field is so strong that even light
cannot escape.
17. H-R Diagram
• The Hertzsprung-Russell Diagram is a graphical
tool that astronomers use to classify stars
according to their luminosity, spectral type,
color, temperature and evolutionary stage.
