W8 L2 - Flashcards
What is the size limit for Earth-like life?
About 2 Earth radii
How can a planet recycle nutrients onto its surface for life to use?
Plate tectonics
What might a planet need to protect itself from solar storms?
Magnetic fields
Why might large stars not be a good place for an Earth-like planet to develop life?
Large stars have a short lifetime
What is the risk of being close to a small star?
Solar flares and radiation
How many Earth-like planets were found around Trappist-1?
Seven!!
What is the name for balance in a star?
Hydrostatic equilibrium
What is the name for the substance in starts where electrons have been stripped?
Plasma
What part of the sun do we see in a total eclipse?
The corona
What are the letter types of stars from hottest to coolest?
O B A F G K M
What is the mnemonic for star category types?
Oh be a fine girl kiss me (or guy, or non-binary individual)
What diagram is used to categorise stars?
The Hertzsprung-Russell diagram
What does the HR-diagram have on its axes?
Vertical = brightness cf Sun; horizontal = T(K) from hot to cool
How much bigger than the sun is the largest known star?
2,000 times bigger than the Sun
Why do M dwarf stars have strong magnetic fields?
There is a lot of plasma moving in the convective zone
What is a downside of being close to a M dwarf star?
Frequent solar flares due to tangled magnetic flares
In FGK stars how big are the radiative and convective zones compared with each other
Similar in size
What happens as FGK stars heat up?
The radiative zones gets bigger and the convective smaller
How big is the radiative zone in OBA stars compared with the convective zone?
Very large
How long do OBA stars last?
Tens of millions of years
What kinds of stars are on the instability strip?
Variable stars
What element gets double ionised in a variable star on the instability strip?
Helium in an ionised helium layer
What is the difference in the size of radiative and convective zones in O stars vs M stars?
O have very large radiative zones, M have very large convective zones
