Ch. 11 Flashcards
Preferred place to look for habitable planets
Around stars
Large clouds of gas collapse to form
multiple star system, or a single star
Stars are born when?
when hydrogen begins to fuse to helium in the core
Core helium burning
when all the hydrogen is used up it starts fusing helium to heavier elements
Most fundamental property of a star
Mass, it determines its surface temperature luminosity and lifetime
Our sun is what class of star
G2
O and B stars in terms of favourability for life
Emit their light in UV which is unsuitable for life
A and F stars in terms of favourability for life
Emit their light in UV and break fragile chemical bonds, with an ozone layer simple life could develop
G K and M stars
Long life times and have habitable zones
K and M star habitable zones
Smaller and closer to the star
Brown dwarfs
No habitable zone, not hot enough for fusion
Multiple star systems stable planetary orbits
The planet orbits both stars at the same time, the planet orbits only one
Definition of a planet
orbits a star, is large enough so its gravity makes it round, cleared debris from its orbital path
Doppler effect
any wave phenomenon is characterized by its speed, wavelength and frequency
