Final Flashcards
What is the minimum temperature needed for nuclear fusion in the core?
10-15 million K
__% of the Sun’s mass is its inner half.
90%
What are neutrinos?
- Weakly interacting
- Low mass
- Fast
- Neutral particles
Needed to conserve angular momentum in beta decay (transforming into the next periodic element).
Neutrinos don’t usually interact with anything. When they do something, what do they do?
They can hit a neutron to produce a proton (beta decay).
Trillions of neutrinos pass through you every second. What was the rate of neutrino
detections for the Sudbury Neutrino Observatory?
About 3 neutrinos per hour.
What was the Solar Neutrino Problem? And the solution?
Early measurements only detected 1/3rd of the predicted amounts of neutrinos.
Turn’s out, there are three types of neutrinos, which oscillate between each other freely. We were only designing our detectors to detect one type.
Oscillations between neutrino types prove…
Neutrinos have mass!
Because of oscillation, the three types can’t have equal mass (or else there wouldn’t be different types).
What is helioseismology?
Like neutrinos, another way to study the interior of the Sun.
It’s the study of the sound waves produced due to the Sun’s pressure fluctuations.
Explain how we study helioseismology. (The Sun is an instrument?)
Sound waves bounce off the Sun to create vibrations with Doppler Shifts! The sound waves vary in pitch depending on the properties of the Sun (yup, it’s an instrument).
Explain the Sun’s Drunkard’s Walk.
Photons are produced from the core, and take a super long time to escape the Sun, since its path is completely random; scattering off & getting absorbed by other particles.
How long can it take for a photon to escape the Sun’s radiation zone?
Drunkard’s Walk = 10^5 - 10^6 years
Why does the Sun’s energy transport change from radiation (radiation zone) to convection (convection zone)?
Due to the decrease in temperature- different modes of heat.
Is energy transport the same in all star types?
Nope, it depends on mass/size –> layers.
Solar Chromosphere vs Corona
Chromosphere = outer activity layer (small red spots around solar eclipse)
Corona = outer atmosphere (white flashes around solar eclipse)
If you took a spectrum of the chromosphere during a solar eclipse, what would you see?
Emission lines (emitting photons).
What do Kirchhoff’s 3 laws imply? What are they?
They imply the way light and matter interact.
- Hot dense objects = continuous spectra
- Cool diffuse gas in front of a hot source = absorption spectra
- Diffuse gas against a dark background = emission spectra
What is a blackbody? What is a blackbody spectrum?
Blackbody: An ideal body that absorbs all incoming energy and emits a continuous spectrum of photons.
Blackbody Spectrum: The specific, continuous spectrum of a blackbody’s thermal radiation depending on its temperature.
What is the solar photosphere? Its significance?
The layer just below the active surface/chromosphere.
It’s the source of the Sun’s blackbody spectrum, and is broken into granules (top-of-convection bubbles) and sunspots.
Why are sunspots dark?
They’re cooler than the rest of the surface.
What are some applications/connections between the Sun’s magnetic field and different characteristics?
- Sunspots = pairs of spots from which magnetic field lines are concentrated and from to & from
- Flared & Prominences = twisted field lines
- Coronal Mass Ejections = giant bursts of releasing concentrated field lines (launch ionized material at Earth = solar winds = interaction with Eath’s magnetic field = auroras)
The number of sunspots indicates ____________________.
Solar activity.
Few = calm/weak
Many = angry/strong
What’s the significance of the number 11 concerning the Sun?
The Sun has an 11-year cycle in the number of sunspots, and its magnetic field reverses every 11 years.
What is the Interstellar Medium (ISM)? What is it best observed in?
The stuff (gas, dust & radiation) between stars.
Bets observed in infrared & radio wavelengths (real red/cool stuff).
A classmate suggests that the density of stars is almost constant everywhere in the disk of the Milky Way galaxy. Is this classmate correct?
Not at all