Final astronomy test

star spectra order

OBAFGKM

hottest star

b-type

longest lived stars suitable for life

GKM

most common star

K

habitable zone

distance where liquid water can exist

depends on stellar luminosity → closer habitable zone

stars closest to habitable zone

m-type

radial velocity

measures star’s motion toward/away → doppler shifts

radial velocity with planets

larger planets → larger signals

most sensitive to close-in planets

transit method

detects planets that pass in front of star → blocks light

transit method strong signal

large planet, close to star

exoplanet occurrence

1 in 3 stars host a planet

FGK- type stars

exoplanet occurrences 2

similar to sun → life potential

M-type may flare too much

OBA stars → short lifetimes, less likely for life

special relativity and time dilation

time is relative: moving clocks run slower

twin paradox

traveling twin→ younger upon return

time things

time affects biological processes like aging

time dilation

affects biological aging and decay

moving clock

they move slower relative to stationary observers