⭐️W6 L1 - Powering stars - The power of stars Flashcards
What process powers the stars?
How many times larger than the Earth is the Sun’s diameter?
About 109 times larger
Who discovered the relationship between period & luminosity in Cepheid variable stars?
Henrietta Swan Leavitt
In 1920, who published a paper describing fusion within stars?
Sir Arthur Eddington
What does the atomic number of an atom refer to?
The number of protons in its nucleus
What particle stabilises the nucleus?
The neutron
What is the name for the form of hydrogen with one proton and one neutron?
Deuterium
What is the electrostatic force?
The short range attraction or repulsion between particles due to their electric charge
What’s another name for the electrostatic force?
The Coulomb Force
What is the name for the repulsive process caused by electric charge?
Coulomb repulsion
What force holds protons together if they get close enough?
The strong nuclear force
How big is a femtometer in scientific notation?
1 x 10⁻¹⁵ metres
What is nuclear fusion?
The process of overcoming electrostatic repulsion between protons to join atomic nuclei and make new atoms.
How many Hydrogen atoms do you need to fuse to make one Helium atom within a star?
Four, which gives one Helium atom and two Hydrogen atoms
What is the temperature of the surface of the sun (in Kelvin)?
About 5,000 Kelvin
What is the temperature at the core of the sun?
About 15 million K
What is the density of the Sun at the core compared with water?
About 40 times that of water
How much Hydrogen does the Sun fuse per second?
6 x 10⁻¹¹ kg/s
What is the mass of the Sun
2 x 10³⁰ kg
What are the two opposing expansion and contraction forces in the Sun?
Contraction from gravity, expansion from the energy of fusion
What is the balance of expansion and contraction forces in the Sun called?
Hydrostatic equilibrium
Moving out from the core of the Sun, what is the first zone of energy transfer called?
The radiative zone
What zone is found outward from the radiative zone in the sun?
The convective zone
Roughly how big is a convection cell on the surface of the Sun?
About the size of Texas
When the Sun’s high temperatures strip electrons from atoms what does it produce?
Plasma
What produces the Sun’s magnetic field?
Circulating plasma
How long between solar minima?
11 years
At a solar minimum what shape are the Sun’s magnetic fields?
Aligned like a bar magnet
At solar maximum, what shape are the Sun’s magnetic fields?
Messy
Are there more sunspots at solar minima or maxima?
Solar maxima
Are sunspots hotter or cooler than the rest of the surface of the Sun?
Cooler
What holds plasma in place to cool down at the position of sunspots?
The Sun’s magnetic fields
What might generate the cyclical nature of solar cycles?
Feedback loops between magnetic fields and plasma
Why are bigger stars hotter?
The expansion and contraction forces are greater because of the larger size
