Chapter 14 Concepts Flashcards
How does the habitable zone of a star change as the mass, age, and luminosity of the star changes?
The size and width of the habitable zone depend on mass of the star!
So when the mass increases, the habitable zone expands and grows further out. Such is the inverse when it shrinks.
Why do stellar lifetimes affect the habitability of the star?
Lifetimes that are too short may not be around long enough to support the development of intelligent life.
Why is life difficult around an M-type star? 3 Reasons.
1) Very small habitable zone.
2) Tidally locked
3) Violent flares would fuck shit up.
Can we “cheat” the habitable zone (hint: think of examples in our own Solar System)?
The habitable zone is completely related to the SURFACE of the planet, but life could live beneath the surface.
What are potential problems for habitability, even if the planet is in the “habitable zone”?
- The Age of a Star: could explode
- Planetary Mass: can it hold its atmosphere?
- Plate tectonics
- Too much gravity: could intelligent life evolve with powerful gravity
- Bombardments: impacts that could destroy us
- Orbital Eccentricity: you could come into and leave the habitable zone regularly
- Metallicity: the abundance of heavier metals
How is the habitable zone affected by binary stars or stars in clusters?
Binary stars orbit each other (60-70% do).
You either need the two stars to be very close to one another & have the planet very fucking far…
Or, you could have the two stars very far apart, but have the planet orbit one of the stars.
Else, shit will get real, and the planet could be ejected from orbit.
What defines the galactic habitable zone? How is the Sun in the “perfect place” in the galaxy for life?
Too close:
- Too many supernovae
- Subject to explosive energy releases from BH
Too far:
- Not enough heavy metals
We’re outside of the spiral arms,
