unit 8 Flashcards
2/22/24
The star’s apparent motion
- a star’s position once, then again 6 months later
stellar parallax
distance that light travels in one year
light year
a unit of length or distance
- used to measure the large distances to astronomical objects outside the Solar System
parsec
any massive self-luminous celestial body of gas that shines by radiation derived from its internal energy sources
star
a measure of the total amount of energy radiated by a star or other celestial object per second
luminosity
- depends on its its distance from Earth
- the total energy emitted by a star per second
- how bright a star appears from the perspective of observers on Earth
apparent brightness
a number that tells how bright that star appears at its great distance from Earth
apparent magnitude
the magnitude that a star would appear to have if it were located at a standard distance of 10 parsecs
absolute magnitude
the relationship between the stars’ absolute magnitudes or luminosities versus their stellar classifications or effective temperatures.
HR diagram
an enormous cloud of dust and gas occupying the space between stars and acting as a nursery for new stars.
nebula
looks like a star but its core is not yet hot enough for fusion to take place
prostar
fuse hydrogen to form helium in their cores - including our Sun.
main sequence stars
- when main sequence stars run out of hydrogen fuel
- dying stars
- the most massive and most luminous stars
supergiants and giant stars
- blue/white core of the star that is left behind
- a small very dense star that is typically the size of a planet.
- dead main sequence stars
- hot and dim
white dwarfs
a white dwarf that has cooled sufficiently to no longer emit significant heat or light
black dwarfs
- remain of high mass stars
- form by the gravitational collapse of the remnant of a massive star after a supernova explosion
neutron stars
- formed from massive stars
- an area of such immense gravity that nothing—not even light—can escape from it
black holes
if you know the apparent brightness and luminosity can you find the distance
True
objects farther away will have a ______ parallax
smaller
objects closer will have a ______ parallax
larger
which covers a larger distance, 1 light year or parsec
1 parsec
Which Greek Philosopher invented a system of Magnitudes for the brightness of stars?
Hippaechus
True or False
Objects with a negative magnitude appear brighter than objects with a negative magnitude?
True
where on the main sequence does a HIGH mass star begin
upper left hand corner
where on the main sequence does a LOW mass star begin
lower right hand corner
where on the main sequence does a sun like star begin?
the middle
how does the initial mass of the protostar affect a star’s evolution?
The more massive the star, the faster everything happens
