Astronomy Concepts

Absolute magnitude measures intrinsic luminosity—how bright an object would appear if placed at standard distance of 10 ...

Absorption lines are dark lines in a spectrum where atoms in cooler foreground gas absorbed specific wavelengths from ba...

Albedo is the fraction of incoming light reflected by a surface, ranging from 0 (perfect absorber) to 1 (perfect reflect...

Emission lines are bright lines at specific wavelengths in a spectrum, produced when excited atoms/ions emit photons.

The Hertzsprung-Russell diagram plots stars' luminosity (or absolute magnitude) vs temperature (or spectral type/color),...

A light curve is a graph of brightness vs time, revealing periodic variations, eclipses, transits, and explosive events.

Luminosity is the total energy radiated by an object per unit time (intrinsic brightness), measured in watts or solar lu...

An occultation occurs when one object passes in front of another from an observer's perspective, temporarily blocking it...

Parallax is the apparent shift in a star's position when viewed from opposite sides of Earth's orbit, the primary direct...

Spectral classification categorizes stars by surface temperature via absorption line patterns, using OBAFGKM sequence.

A spectrum is light dispersed by wavelength, revealing composition, temperature, velocity, and physical conditions of as...

A transit is when a smaller object passes in front of a larger one (opposite perspective from occultation, but often use...