Vocabulary 1
a star's outer shell from which light is radiated
photosphere
the reaction in which two atoms of hydrogen combine together, or fuse, to form an atom of helium
nuclear fusion
a scatter plot of stars showing the relationship between the stars' absolute magnitudes or luminosities versus their stellar classifications or effective temperatures
Hertzsprung-Russell Diagram
the second of the three main layers in the Sun's atmosphere
chromosphere
a cloud of gas and dust in outer space, visible in the night sky either as an indistinct bright patch or as a dark silhouette against other luminous matter
nebula
the continuous flow of charged particles from the sun which permeates the solar system
solar wind
a group of stars forming a recognizable pattern that is traditionally named after its apparent form or identified with a mythological figure
constellation
a diagonal band on the Hertzsprung Russell diagram containing about 90% of all known stars
main sequence
outermost region of the Sun's atmosphere, consisting of plasma (hot ionized gas)
corona
a contracting mass of gas which represents an early stage in the formation of a star, before nucleosynthesis has begun
protostar
a spot or patch appearing from time to time on the sun's surface, appearing dark by contrast with its surroundings
sunspot
a system of two stars in which one star revolves around the other or both revolve around a common center
binary star
Describe how temperature is graphed from left to right on an H-R diagram.
hot to cold
temperature of the sun
5800 K
the collapsed core of a massive supergiant star; except for black holes and some hypothetical objects, these are the smallest and densest currently known class of stellar objects
neutron star
a brief eruption of intense high-energy radiation from the sun's surface
solar flare
the intrinsic brightness of a celestial object (as distinct from its apparent brightness diminished by distance)
luminosity
Where are red supergiants located on an H-R diagram?
upper right
Which stars are hottest?
white dwarfs
a region of space having a gravitational field so intense that no matter or radiation can escape
black hole
the splitting of atoms, either by radioactive decay or by collisional impact
nuclear fission
a celestial object, thought to be a rapidly rotating neutron star, that emits regular pulses of radio waves and other electromagnetic radiation at rates of up to one thousand pulses per second
pulsar
upper left - these are blue giants
Describe the nuclear reactions that happen within the sun.
nuclear fusion - hydrogen atoms, which each have one proton, collide to form helium atoms, which each have two protons
a star that suddenly increases greatly in brightness because of a catastrophic explosion that ejects most of its mass
supernova