Test #3 Definitions & Examples Flashcards
Definition of star?
a fixed luminous point in the night sky which is a large, remote incandescent body like the sun.
EX: star.
Definition of an apparent magnitude?
the measure of the brightness or luminosity of a star or other astronomical object.
EX: The Sun is -26.7
Definition of black hole?
a region of space having a gravitational field so intense that no matter or radiation can escape.
EX: Sagittarius A is one of the famous black holes, its at the heart of the milky way.
Definition of absolute magnitude?
the magnitude (brightness) of a celestial object as it would be seen at a standard distance of 10 parsecs. EX: Sirius has an absolute magnitude of only 1.4, which is still brighter than the Sun.
Definition of main sequence?
a series of star types to which most stars belong, represented on a Hertzsprung–Russell diagram as a continuous band extending from the upper left (hot, bright stars) to the lower right (cool, dim stars).
EX: One of the main sequence stars is Betelgeuse.
Definition of electromagnetic radiation?
Electromagnetic radiation is energy that is transmitted at the speed of light through electric and magnetic fields.
EX: infared waves.
Definition of nebula?
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.
EX: The Cat’s Eye Nebula, is a planetary nebula.
Definition of light-year?
a unit of astronomical distance equivalent to the distance that light travels in one year, which is 5.88 trillion miles.
EX: An example of a light-year is over five trillion miles.
Definition of supergiant?
a very large star that is even brighter than a giant, often despite being relatively cool.
EX: Antares
Definition of nuclear reaction?
a change in the identity or characteristics of an atomic nucleus that results when it is bombarded with an energetic particle, as in fission, fusion, or radioactive decay.
EX: The most notable nuclear reactions are the nuclear chain reactions in fissionable materials that produce induced nuclear fission
Definition of gravity?
the force that attracts a body toward the center of the earth, or toward any other physical body having mass.
EX: The force that causes a glass you drop to fall to the floor.
Definition of white dwarf?
a small very dense star that is typically the size of a planet. A white dwarf is formed when a low-mass star has exhausted all its central nuclear fuel and lost its outer layers as a planetary nebula.
EX: Sirius B is a white dwarf star.
Definition of nucleosynthis?
the cosmic formation of atoms more complex than the hydrogen atom.
EX: carbon-14, produced from nitrogen-14 in the atmosphere by cosmic rays.
Definition of H-R diagram?
a scatter plot of stars showing the relationship between the stars’ absolute magnitudes or luminosities versus their stellar classifications or effective temperatures.
EX: It’s a chart to show the specifics of the relationships stars have with their terms.
Definition of giant?
an imaginary or mythical being of human form but superhuman size.
EX: Goliath in the story of “David and Goliath.”
