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astronomy chapter 20

chapter 20
STUDY
PLAY
a star no matter what its mass spends most of its life
as a main sequence star
when a star inward gravity and outward pressure are balanced, the star is said to be
in a hydrostatic equilibrium
what spectral type of star tht is still around formed most recently
O type
at which stage in a sun-like star's life is its core the least dense
Main sequence
which of the follwoing elements contained in your body is NOT formed in the cotrd of stars during thermonuclear fusion
hydrogen
what temperature is needed to fuse helium into carbon
100 million K
the "helium flash" occurs at what stage in stellar evolution
red giant
during the hydrogen shell burning phase
the star grows more luminous
a star is on the horizontal branch of the HR diagram,...then
it is burning both hydrogen and helium
what inevitably forces a star like the sun to evolve away from being a main sequence star
helium builds up in the core, while the hydrogen burning shell expands
just as low-mass main sequence star runs out of fuel in its core, it actually becomes brighter...
the core contracts, rasing the temperature and increasing the size of the region of hydrogen shell burning
in the HR diagram steps labeled 8-9 is the ....branch
red giant branch
in the HR diagram steps labeled 10-11 is the ....branch
asymptotic giant branch
in the HR diagram steps labeled 10 is the ....branch
horizontal branch
in the HR diagram steps labeled at which point on the graph does helium flash occur
the red giant branch (9)
in the HR diagram steps labeled 11-12 is the ....branch
planetary nebula
in the HR diagram steps labeled 13-14 is the ....branch
white dwarf
which of these will the sun probably become in the distant future
planetary nebula
which of these is true regarding planetary nebulae
some are spherical, but most have bipolar struccture
a solar mass star will evolve off the main sequence when
it builds up a core of inert helium
what is a planetary nebula
the ejected envelope, often bipolar , of a red giant surroundings a stellar core remenant
what are black dwarfs
cooled off white dwarfs that no longer glow visibly
the order of evolutionary stages of a star like the sun would be Main sequence, giant, planetary nebula and finally
white dwarf
compared to our sun , a typical white dwarf is.....
about the same mass and a million times higher density
virtually all the carbon-rich dust in the plane of the galaxy originated in
low-mass stars
a high mass star dies more violently than a low mass star because...
it generate more heat and its core eventually collapses very suddendly
isolated main sequence stars as massive as 10-12 times the mass of the sun may still manage to avoid going supernova why?
because it can also have strong stellar winds
which describes the eveolutionary track on the HR diagram for the most massive stars
horizontallly right
as a 4-10 solar mass star leaves the main sequence on its way to becoming a red supergiant, its luminosity
remains roughly constant
in the evolution of massive stars, what is th esignificance of the temperature 600 million kelvin
it is the temperature need for carbon fusing into heavier elements
the brightest stars of a young open cluster will be
massive blue main sequence stars
what chracteristic of a star cluster is used to determine it sage
the main sequence turnoff
what is the typical age for a globular cluster associated with out milky way
10-12 billion yrs
the brightest stars in a young open cluster will be
massive blue stars at the top of the HR diagram
compared to a cluster containing type O and B stars, a cluster with only type F and cooler stars will be..
older
what is a typical age for a globular cluster
12 billion yrs
in globular clusters the brightest stars will be
red supergiants
in a fairly young star cluster, if the most massive star are swelling up into giants, the least massive star are
still evolving toward their ZAMS positions
the bightest star in aging globular cluster will be
red supergiants like Betelguese and antares
noting the turnoff mass in a star cluster allows you to determine its
age
which is used obsevationally to dtermine the age of a star cluster
the luminosity of the main sequence turnoff point
what is the unsuaual result of mass transfer in the Algol binary system
a helium white dwarf
the roche lobe of a star in a binary star system...
in, in terms of the star's gravity its "zone of influence"
the most famous case of a massive hot star orbiting a more evolved but presently less massive red giant is the eclipsing binary,...
ALGOL
Mass transfer in binaries occurs when one giant swells to reach the
roche lobe
that brighter sirius A weighs 3 solar masses, but the white dwarf sirius B is only about one solar mass implies
that the collapsed companion transfered mass to sirius A
you observed a low mass helium white dwarf, what can you conclude
it is part of a binary star system
which star in globular clusters are believed to be examples of mergers
Blue stragglers