Stars - The Main Sequence Stage
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Transcript of Stars - The Main Sequence Stage
THE STARSThe Main Sequence Stage
By Giulia Greco, 5D
The Birth of a new star
Gravity
Pressure
Compression of the central core
Result: increase in temperature 4 million °C
Material in new star
• Hydrogen (about 75 %)
• Helium (about 24 %) • Others elements (about 1 %)
• over 90 % of all atoms• orignated by the Big Bang
Hydrogen Fusion
When temperature = 5,5 million °C
Collision of hydrogen’s protons
FUSION
migrates up to the surface and escapes into space
Stable fusion equilibrium
• Hydrogen fusion explosion• Gravity compression
Prevents the destruction of the star
Particular size
Solar Wind
• Explosions in the core high temperature (over 11 million °C)
• Hot matter fly off into space
Like a wind•1 million km per hour• Blows away the remaining gas
Regular main sequence
• Size: similar to Sun• Color: from white to yellowish
Surface temperature
Hot temperature
blu to blu-white
average temperature
white to yellowish
Cold temperature orange to red
HR Diagram• Hot fast short• Cold slow long
Red Dwarf
• most common Main Sequence star size
• 10% to 50% the size of Sun• fusion rate: low• need telescopes • PROXIMA CENTAURI
Up to 70 % of all star in Milky Way galaxy are Red Dwarf
Yellow Giants or White Giants
• 5 to 50 times larger than Sun• fusion rate: fast
• naked eyeBecause: mass = greater
core temperatures = hotter
Blue or Blue-White SuperGiants
• Hydrogen to last only 100 million yearShort life
• SummaryBlue Supergiants
Blue – White Supergiants
Yellow or White GiantsYellow to White Regular Stars
Red Dwarfs
The Sun• Surface temparture: 5500°C• Core temperature: over 14 milllion °C• It is in equilibrium• Hydrogen fusion for about 5 bilion more years• Solar wind
Proxima Centauri
• The closest star to the Sun• Red Dwarf : 8 % the size of sun• Invisible from Earth• no plants or solar system
Rigel Kentaurus
• Near to Proxima Centauri triple star system• Pair of yellow main sequence star:
Kentaurus A and B
Similar in size, temperature age to our Sun
Sirius A – Canopus - Rigel
• Stars larger than our Sun– Sirius A: twice as large as our Sun
White Main Sequence star– Canopus : 62 times larger than our Sun White to Yellow-White Giant star– Rigel: 68 times bigger in diameter than our Sun
Blue – White Supergiant