Physical Science Star Terms Flashcards
core
the central region of the sun where nuclear fusion occurfs
radiation zone
a region of closely packed plasma outside the core of the sun, where energy is transferred by the absorption and reradiation of light
convection zone
the region inside the sun where thermal energy is transferred outward mainly by convection currents
photosphere
the thin, intermost layer of the sun’s atmosphere
chromosphere
the middle layer of the sun’s atmosphere
corona
the outermost layer of the sun’s atmosphere
sunspots
an area of gas in the sun’s photopshere where it’s cooler
prominences
huge loops of gas from sunspot regions and extend upward from the photosphere into the chromosphere and sometimes to the corona.
solar flares
a dramatic eruption on the sun’s surface
light year
the distance light travels in a vacuum in a year
parallax
an apparent change in position of an object with respect to a distant background
apparent brightness
the brightness of a star as it appears from Earth
absolute brightness
a description of how bright a star really is
H R Diagram
the Hertzprung-Russell diagram, graph of surface temp. versus absolute brightness of a sample of stars
Main sequence stars
90% of all stars, fusion matches gravity
supergiants
a very large, massive, bright star ranging in size from 100 to 1000 time diameter of the sun
giants
a large massive bright star that’s somewhat smaller and fainter than a supergiant
white dwarf
a small, dense dim remains of a low/medium mass star
nebula
a large cloud of gas and dust spread out over a large volume of space
protostar
a contracting nebula with enough mass to form a star
planetary nebula
a glowing cloud of gas surrounding a dying star
supernova
an enormous explosion in which the by products of a star of fusion are flung into space
neutron star
the dense core left after a high mass star has exploded
pulsar
the spinning neutron star that appears to give off pulses of radio waves
black hole
an object whose surface gravity is so great that not even electromagnetic waves can escape from it
constellation
a group of stars that appears to form a pattern as seen from Earth
binary star
a star system with two stars that revolve around each other
associations
a temporary grouping of bright, young clusters
globular cluster
a large spherical shaped group of older stars that usually lacks sufficient amounts of gas and dust to form new stars
galaxy
a huge group of individual stars, star systems, star clusters, dust, and gas bound together by gravity
spiral galaxies
bulge of stars at enter and arms, looks like a pinwheel
barred spiral galaxies
a spiral galaxy in which spiral arms extend outward from a bar running through the center of the galaxy
irregular galaxies
a galaxy with a disorganized appearance
quasars
enonmously bright centers of a young star
hypervelocity stars
stars with velocities that are substantially different from that expected for a star belonging to the normal distribution of stars in a galaxy.
Magnetar star
a type of neutron star believed to have an extremely powerful magnetic field
galaxy mergers
occur when 2 galaxies collide
