Our star sol
description
Transcript of Our star sol
OUR STAR SOL
GOALS
• You will have a basic understanding of how a star functions and how they convert matter into energy• You will discuss and write down key
vocabulary related to the structure and functions within stars
JUST TO RECAP THE STATS WE KNOW…
• Age: 4.6 Billion years• Diameter: 1,391,000 km• Mass: 1.989 x 10^30 kg• It’s a star• It’s not on fire!!!!!
HISTORY… OR SOMETHING LIKE IT
• The Sun was revered by many ancient peoples.
EGYPTIANS
• The sun was revered as Ra.• Carried across the sky in a Barque (ship)• Accompanied by lesser gods for the daily
journey
ANCIENT GREEKS
• The sun was hailed as Helios.• Carried across the sky in a chariot drawn by
fiery horses.
ROMANS
• Celebrated the birthday of the Sun as a holiday called “Sol Invictus,” literally “Unconquered Sun.”
MORE RECENT GREEKS
• The location of where the sun rose in the sky gave rise to the Zodiac.• It was considered a planet
WHAT WE KNOW ABOUT THE SUN
• It is divided into 4 distinct layers• Core• Radiative Zone• Convective Zone• Photosphere• Above this is the Atmosphere of the Sun
THE CORE
• 20-25% of the radius of the Sun• 150 x density of water• 15.7 million K• 99% of the energy in the Sun is produced
here
DETAILS OF FUSION
• Proton-Proton fusion happens 9.7 x 10^37 times each second in the core• 6.2 x 10^11 kg /s of Helium is produced each
second in this reaction• About 1 x10^-13 x the mass of the Earth
each second or• 3.1169 x10^-19 x the Sun’s mass (slow
enough for billions of years worth of fuel)
DETAILS OF THE FUSION CONTINUED…
• 0.7% of the mass of Helium produced is released as energy• This equates to 3.846 x 10^26 Watts of
energy per second• 4.875 x 10^24 80 Watt lightbulbs for 1
second or…• One 80 Watt bulb for 1.524 x 10^17 years
THE RADIATIVE ZONE
• 25-70% the radius of the Sun• Temperature drops to between 7 and 2
million K
DETAILS OF THE RADIATIVE ZONE
• Temperature gradients within the zone are to high for convection to happen• Energy is transferred by photons being
emitted and absorbed by atoms
THE CONVECTIVE ZONE
• From about 70% of the radius of the sun to 200,000 km below its surface• Temperatures low enough that atoms are
no longer ionized• Densities low enough that convection can
occur
CONTINUED…
• Material is heated at the surface of the radiative zone and rises up where its energy is transferred to the photosphere• Its temperature drops to 5700 K and then
sinks back to the radiative zone to be reheated
PHOTOSPHERE
• The visible surface of the Sun• 10 to 100’s of kilometers thick• Observations of this layer resulted in the
discovery of Helium