Main Sequence Stars and Our Sun

These flashcards cover key vocabulary concepts related to the lecture on stars and solar activity.

Solar Activity Cycle

The cyclical variation in solar activity, affecting sunspots, solar flares, and solar storms.

Sunspots

Dark areas on the sun's surface, associated with magnetic activity.

Coronal Loops

Structures formed by magnetic field lines that trap plasma above the sun's surface.

Solar Flares

Explosive bursts of energy resulting from the snapping of magnetic field lines.

Coronal Mass Ejections

Massive bursts of solar wind and magnetic fields rising above the solar corona or being released into space.

Differential Rotation

The phenomenon where different parts of the sun rotate at different rates.

Magnetic Field Lines

Invisible lines that represent the strength and direction of a magnet's pull, critical in solar activity.

Brown Dwarfs

Stars that failed to ignite fusion due to insufficient mass, typically less than 0.08 solar masses.

Electron Degeneracy Pressure

The quantum mechanical pressure that prevents two electrons from occupying the same quantum state, halting collapse in stars.

Photon Radiation Pressure

The outward pressure exerted by photons, which can lead to the disintegration of stars exceeding certain mass limits.

Molecular Cloud

A dense region of gas and dust in space where star formation occurs.

Protostar

An early stage of star formation, before nuclear fusion begins.

Main Sequence Star

A stable phase in a star's life where hydrogen is fused into helium in the core.

Thermal Pressure

Pressure that arises from thermal energy, countering gravitational collapse in stars.

Helium Flash

A rapid onset of helium fusion in a star's core after hydrogen fusion ceases.

Asymptotic Giant Branch

A late stage in a star's evolution where it expands and cools as it exhausts its nuclear fuel.

Planetary Nebula

A shell of gas ejected from a red giant star, forming a nebula around a white dwarf.