practice questions astronomy

what population of stars is old?

population ii

what population of stars is young?

population i

whats the order of luminosity for beyer designated (greek letter) stars?

brightest stars to least bright

what is the purpose of the messier catalog?

to help astronomers distinguish between non comet objects and comets

how does a black hole grow?

accretion and merging with other black holes

how does a black hole shrink?

hawking radiation/starved

if white dwarf stars are no longer generating fusion energy, why wont they collapse into a black hole?

they are made of a degenerate gas

eventually high mass stars are unable to continue fusion of heavier and heavier elements when they…

accumulate too much iron in their cores

Neutron stars have strong radiation beams at their poles due to

Their very strong magnetic field

A type i supernova happens after

mass in a binary star system falls onto a white dwarf, igniting a runaway fusion event

If light doesnt have mass, how can gravity affect the path of light?

heavy masses warp spacetime causing light to have its path deflected

Galaxies can evolve by…

stealing gas/stars from other galaxies

What is the force responsible for the accelerating expansion of the universe?

gravity

We call it dark matter because…

It doesnt give off light

Dark energy is…

Causing the universe to grow at an accelerated rate

At the universe gets smaller in the past it get hotter because…

Radiation dominates the universe

If i measure my variable star to have a very long period, what can i say about that star?

It has a high luminosity

In the spiral arms of the milky way, you will find…

a supermassive black hole

Redshift z=1000 would indicate

A time near the beginning of the universe

Irregular galaxies dont fit into our usual classification scheme. They may have recently…

-merged with another galaxy

When stars accumulate too much helium in the core they begin to…

Grow in size

Hii regions glow with light because…

They absorb and radiate light from nearby stars

Astronomers are very interested giant molecular clouds because…

Stars are formed from these clouds

While in the protostar stage, a nearly forming star will be…

More luminous (higher luminosity) than it will be when it gets to the main sequence

What physical feature will determine where a new star ends up on the main sequence

Mass

Why is parallax only useful for nearby stars?

The angles are small and hard to measure

If star A has an absolute magnitude of 4 and an apparent magnitude of 2 and star b has an absolute magnitude of 2 and an apparent magnitude of 2, which star is closer to earth?

Star A

If star A has an absolute magnitude of 4 and an apparent magnitude of 2 and star b has an absolute magnitude of 2 and an apparent magnitude of 2, which star is closer to earth?

Star A

What is the correct order of spectral classification?

OBAFGKM

Astronomers define metals to be…

Anything that is not hydrogen or helium

There is a relationship between the luminosity of a star and…

Its mass, radius, and temperature

what are the types of binary star systems?

detached, semi-detached, contact

what is the vertical axis on an HR diagram?

luminosity, increase as you go up

what is the horizontal axis on an HR diagram?

temp, increase as you go left

what is the type of nebulae known as hii

big cloud of gas (plasma, ionized hydrogen) heated up by nearby stars

what are planetary nebulae?

when a star goes from giant to white dwarf and experiences mass loss in slow motion faux-explosion, leaves a huge cloud of gas behind, nothing to do with a planet, too hot for star birthing

what is a supernova remnant?

what is left behind when a star explodes, can contain a neutron star or a black hole, too hot for star birthing

what are old neutral hydrogen clouds (h1)

they contain atomic hydrogen that are very cold but not bonded together

what are giant molecular clouds

are the type that yield stars, in a state of hydrostatic equilibrium until something triggers overdensity, contain molecular hydrogen (bonded)

what is a type 1 supernova?

a thermonuclear explosion that occurs when a white dwarf star, often in a binary system, reaches a critical mass and catastrophically implodes

what is a type 2 supernova?

results from the rapid collapse and violent explosion of a massive star.