astronomy chapter 20

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chapter 20

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

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