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Main Sequence Stars

Main sequence stars are stars, like our Sun, that fuse hydrogen atoms together to make helium atoms in their cores. For a given chemical composition and stellar age, a stars' luminosity, the total energy radiated by the star per unit time, depends only on its mass. Stars that are ten times more massive than the Sun are over a thousand times more luminous than the Sun. However, we should not be too embarrassed by the Sun's low luminosity: it is ten times brighter than a star half its mass. The more massive a main sequence star, the brighter and bluer it is. For example, Sirius, the dog star, located to the lower left of the constellation Orion, is more massive than the Sun, and is noticeably bluer. On the other hand, Proxima Centauri, our nearest neighbor, is less massive than the Sun, and is thus redder and less luminous.

our star, the sun

STAR DEATH
the sun will eventually collapse, squeezing the last particles of fuel so tightly that it will reheat and glow bright white. at this stage, a star is known as a white dwarf.

MAKING THE SUN
the universe is made up of countless clouds of gas and dust.around 5 billion years ago, one of these swirling clounds formed a middling -sized star- our sun. the energy released by its burning gas provides the light and warmth necessary for life on earth.

FULL IGNITION
when the temperature at the centre of the embryo star reached about 15 million C (27 million F), nuclear reactions began turning hydrogen into helium, causing it to radiate heat and light.

TOMORROW'S SUN?
when the sun has burnt up the fuel at its centre, it will start to expand rapidly and cool down , and it will become a red giant.

science is fun

selamat datang ke blog saya~

Thursday, 15 September 2011

selamat datang ke blog saya

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