Chapter 15/16: The Sun Flashcards
What is the diameter of the sun?
1.4 x 10^6 km (109 x Earth’s D)
What is the mass of the sun?
2.0 x 10^30 kg (332,000 x Earth’s M)
What is the surface temperature of the sun?
5,800 K
What is the core temperature of the sun?
15,000,000 K
What is the composition of the sun?
92% H and 7.8% He by nuclei (73.4% H and 25% He by mass)
What is the Luminosity of the sun?
3.9 x 10^26 Watts
What are the Layers of the sun? (inner to outer)
Core, Radiative Zone, Convection Zone, Photosphere, Chromosphere, Corona
What are the layers of the Solar Atmosphere?
Chromosphere, Photosphere, Corona
What is the photosphere layer?
It is the visible surface of the sun that we are most familiar with. (not a solid surface)
What does the photosphere layer have?
Granulation, Sunspots, Prominences, Solar Flares
What is a granulation?
They are blotchy spots produced by rising hot gas while the cooler gas sinks down.
What is a sunspot?
A region in the photosphere where the temperature is relatively low which makes it darker than its surroundings (Umbra and Penumbra) that is associated with magnetic fields. (look like bright arcs)
What is an Umbra?
The dark part of the sunspot (3,700 K)
What is the Penumbra?
Slightly less dark part of the Penumbra but still darker than the photosphere layer
What is the sunspot cycle?
The average number of sunspots on the sun varies but is predictable, it reaches a maximum every 11 years then falls to 0 and starts again.
What is the butterfly diagram?
At the beginning of the cycle, sunspots appear far from the equator then closer as the cycle progresses
What causes sunspots?
The sun rotates faster at its equator than the poles called differential rotation.
What is a prominence?
It is an arc of magnetic field and solar plasma (last hours-days).
What is a solar flare?
It is a sudden increase in brightness of a region of the sun, caused by the breaking and reconnecting of magnetic field lines.
What is released in a solar flare?
Large amounts of energy (radiation)
Where do solar flares usually happen?
Near the sun’s surface and close to sunspots.
What is the chromosphere layer?
It is above the photosphere (higher temp) and gives a reddish emission line spectrum (Hydrogen).
What does chromosphere mean?
place where the color comes from.
When can you see the sun’s chromosphere?
During the total solar eclipse
What is the Corona layer?
It is the outer layer of the sun’s atmosphere.
What is the temperature of the corona?
About a million degrees.
What is the corona nearly?
a vacuum
What is Solar Wind?
outflow of coronal gases.
What is the heliosphere?
It is the sun’s reach of influence on its environment.
What is a Coronal Mass Ejection?
A huge blast of high energy particles then followed by vast amounts of solar plasma.
What is an Aurorae?
Some solar wind particles are able to leak through the Earth’s magnetic field at its weaker points (makes cool lights)
What is the proton-proton chain?
A three-step process that converts hydrogen into helium to generate energy (nuclear fusion).
What particles are in the chain?
Proton, Electron, Positron, Neutrino, Gamma-ray photon, deuterium, Helium-3, Helium-4
What is the first step of the chain?
2 hydrogen protons turn into a neutrino, deuterium, positron
What is the second step of the chain?
A hydrogen proton and deuterium turn into an isotope of Helium (2 protons one neutron (Helium-3) and gamma rays. (MUST HAPPEN TWICE)
What is the third step of the chain?
Two Helium-3s turn into a Helium-4 and 2 Hydrogen protons.
Some mass is lost and turned into the sun’s energy (how much).
0.7% (E = mc^2)
What is a neutrino (v)?
It is a weakly interacting neutral particle that travels at nearly the speed of light and has nearly no mass.
What is Hydrostatic Equilibrium?
The inward gravitational force is balanced by outward gas and radiation pressure. (higher temp. = higher pressure)
What is Radiation?
energy transported by photons in the Radiative Zone.
What is Convection?
energy transported by mass motions of the gas in the Convection Zone)
What energy transport is not in the sun?
Conduction
How to construct a model of a star like the sun?
ideas of hydrostatic equilibrium, temperature, and energy transport as a set of equations.
What is Helioseismology?
The sun is so dense that it is opaque - all the light we see comes from the Sun’s surface. Vibration is kinda like a guitar.
