PHY 1455 Astronomy Test 3 Baylor
Terms in this set (65)
what is the first stage for a low-mass star life cycle?
main sequence (hydrogen to helium fusion)
what is the second stage for a low-mass star life cycle?
red giant (no fusion)
what is the third stage (pt. 1) for a low-mass star life cycle?
helium flash ( beginning of helium to carbon fusion)
what is the third stage (pt. 2) for a low-mass star life cycle?
horizontal branch (helium to carbon fusion)
what is the fourth stage for a low-mass star life cycle?
asymptotic branch (no fusion)
what is the fifth stage for a low-mass star life cycle?
planetary nebula explosion (no fusion, cools down)
what is the sixth stage for a low-mass star life cycle?
white dwarf (no fusion)
what part of the h-r diagram is a white dwarf?
lower left quadrant
what part of the h-r diagram is a red giant
upper right quadrant
method/experiment and physical law for temperature?
spectra; wien's law
method/experiment and physical law for radius/volume/size?
luminosity, temperature; stefan-boltzmann's law
method/experiment and physical law for mass?
binary stars; kepler's 3rd law
method/experiment and physical law for radial velocity?
red shift/blue shift; doppler effect
what does standard candle do?
allows you to determine luminosity, which then allows you to calculate distance to object
what are two standard candle methods?
spectroscopic parallax and cepheid variables
what is the measurement for spectroscopic parallax?
what is the 'special' knowledge for spectroscopic parallax?
temperature of a main sequence star
what is the measurement for cepheid variables
pulsing of the brightness
what is the 'special' knowledge for cepheid variables
pulse period is related to luminosity
what is one direct method of determining distance?
parallax (don't need temperature or mass)
true or false: are brightness, luminosity, and distance all related?
if you know brightness and luminosity, what can you find?
what physical property is represented by absolute magnitude?
luminosity: how much energy per second the star produces
what physical property is represented by apparent magnitude?
brightness: how much light is hitting something; depends on position of observer
for a difference of 5 in magnitude, what is the factor?
lower the number on the magnitude scale, the brighter the star
describe the physical system that produces a nova
death of a low-mass star; white dwarf and binary star system pull materials from other stars (red giants) and fuses (fuses to glow bright)
describe the physical system that produces a type 1a supernova
(low-mass) white dwarf and binary star collecting materials white the star practically explodes
describe the physical system that produces a type ii supernova
death of a high-mass star on a regular life cycle
what type of physical system is part of the normal life cycle of a star? what kind of star does it need to be?
type ii supernova; high-mass star
what is the chandrasekhar limit?
the mass limits between a white dwarf and a neutron star (in a type 1a supernova); if a white dwarf exceeds limit, it becomes a neutron star
what is the life cycle of the sun?
about 10 billion years
how many earths would it take to fill the sun?
about 1 million
what is the order of regions of the sun?
core, radiation zone, convection zone, photosphere, chromosphere, corona
what is the photosphere?
the visible surface of the sun
what is the top layer of the convection zone also called?
what is hydrostatic equilibrium?
stability of the sun
what are sun spots?
intense magnetic fields with low temperatures
what is the sun's surface temperature?
around 6000 K
how long is a sunspot cycle?
11 year cycle in which the number of sunspots reaches a maximum and minimum; half the duration of the solar cycle
how long is a solar cycle?
22 year cycle in which the sun's magnetic pole reverse and return to their original configuration
what is the mass of the sun?
what is the radius of the sun?
696,000km (100 earth radii)
what is the average density of the sun?
what is the sun's rotation period?
24.9 days (equator); 29.8 days (poles)
where and how does the sun produce energy?
the core through fusion of hydrogen and helium
what is solar wind?
wind strong enough to 'sail' the solar system
what is the equation that shows the relationship of luminosity and brightness? how is stellar luminosity determined?
distance^2) (inverse square law)
what are the three techniques for determining distance to a star?
parallax, spectroscopic parallax, and variable star
what are sunspots?
dark regions on the surface of the sun around the size of the earth (usually in pairs)
why do sunspots appear?
they are cooler than the rest of the sun and they are regions where the sun's magnetic field is concentrated in leaving and entering the photosphere
where is the yellow giant phase (horizontal branch) on the h-r diagram?
in between red giant and blue giant in the upper portion
where is the red giant region on the h-r diagram?
upper right portion
where is the white dwarf region on the h-r diagram?
lower left region
where are low mass main sequence stars on the h-r diagram?
where are high mass main sequence stars on the h-r diagram?
what is the life cycle of a high mass star?
the core of the star fuses until it has an iron core (iron cannot fuse); becomes a neutron star or black hole
what is a planetary nebula?
death of a star; the outer layers bounce off into space
what is a white dwarf?
a very small, very dense star about the size of a planet
Formed when a low-mass star has stopped fusing and lost its outer layers as a planetary nebula
what is a neutron star?
the remnant of a high mass star -The force collapsing the star was so strong that it combined the protons and electrons to be left only with neutrons
what is a black hole?
the remnant of over 3 solar masses (after a star goes super nova)
to find the masses of both stars in a planetary system, what must you know?
velocity, period, distance
how is the mass of a star determined?
by using kepler's 3rd law and using binary stars as a form of measurement
what is the mass range for white dwarfs?
< 8 to 10 solar masses
what is the mass range for stars to become neutron stars or black holes?
> 8 to 10 solar masses