Nuclear Reactions and Stellar Evolution Flashcards

Flashcards covering nuclear reactions, stellar evolution, and the Big Bang theory.

Alpha Decay

A type of radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus) and transforms into a different atomic nucleus, with a decrease in atomic number by 2 and mass number by 4.

Beta- Decay

A type of radioactive decay in which a beta particle (electron) is emitted from an atomic nucleus, increasing the atomic number by 1 while the mass number remains the same.

Beta+ Decay

A type of radioactive decay in which a positron is emitted from an atomic nucleus, decreasing the atomic number by 1 while the mass number remains the same.

Gamma Decay

A type of radioactive decay in which an atomic nucleus emits a gamma ray photon, without changing the atomic number or mass number of the nucleus.

Nuclear Fission

A nuclear reaction in which the nucleus of an atom splits into smaller parts (lighter nuclei), often producing free neutrons and photons, and releasing a large amount of energy.

Nuclear Fusion

A nuclear reaction in which two or more atomic nuclei combine to form a single heavier nucleus, releasing a large amount of energy.

Proton-Proton Chain Reaction

A series of nuclear fusion reactions that convert hydrogen nuclei into helium nuclei, releasing energy which is the primary process by which energy is produced in main sequence stars.

CNO Cycle

A catalytic cycle of nuclear fusion reactions that use carbon, nitrogen, and oxygen isotopes as catalysts to convert hydrogen into helium, and is the dominant process for energy generation in stars more massive than the Sun.

Low Mass Star Life Cycle

A star with a relatively small mass will progresses from a main sequence star to a red giant, then to a planetary nebula, and finally to a white dwarf.

Large Mass Star Life Cycle

A star with a larger mass experiences a lifecycle that goes from a main sequence star to a red supergiant, then explodes as a supernova, leaving behind a neutron star.

Massive Star Life Cycle

The lifecycle of a very large star where it transitions from a main sequence star to a red supergiant, and then explodes as a supernova, leaving behind a black hole.

Big Bang Theory

The prevailing cosmological model for the universe, stating that the universe was once in an extremely hot, dense state that expanded rapidly, and has been cooling and expanding ever since.

Redshift

The observed phenomenon where the light from distant objects in the universe is shifted towards the red end of the spectrum due to the expansion of the universe, indicating that these objects are moving away from us.

Cosmic Microwave Background (CMB)

The thermal radiation (black body radiation) left over from the time of recombination in Big Bang cosmology.