Why do stars exist?
Stars form from an accumulation of gas and dust, which collapses due to gravity and starts to form stars. Stars, like our own Sun, have not always been around. Stars are born and die over millions or even billions of years. Stars form when regions of dust and gas in the galaxy collapse due to gravity.
Which is the best description of a star?
Star, any massive self-luminous celestial body of gas that shines by radiation derived from its internal energy sources. This article describes the properties and evolution of individual stars. Included in the discussion are the sizes, energetics, temperatures, masses, and chemical compositions of stars.
How are the different types of stars classified?
Types of Stars. Astronomers sort stars into categories according to their spectral characteristics – that is the information contained in the light they radiate. The general categories are O, B, A, F, G, K, M, R, N, T, Y, and group stars (and stellar objects) by their temperatures, luminosities, and colors.
How are the Stars in the Universe related?
Of the tens of billions of trillions of stars composing the observable universe, only a very small percentage are visible to the naked eye. Many stars occur in pairs, multiple systems, or star clusters. The members of such stellar groups are physically related through common origin and are bound by mutual gravitational attraction.
What are some facts about the life of a star?
1 A star is born. The life cycle of a star spans billions of years. 2 All that glitters. Some stars shine more brightly than others. 3 Big bang. Massive stars eschew this evolutionary path and instead go out with a bang—detonating as supernovae. 4 Looking up.