Astronomy: Stars, Black Holes, and Neutron Stars

Stellar Classification

• Stars are categorized based on size, temperature, and spectra.
• Spectral classification focuses on the peak emission wavelength to determine surface temperature.
• A star's color and brightness vary significantly with its size.

Black Holes

• Regions in space where no object or light can escape.
• Existence is supported by phenomena attributed to black holes, although they cannot be directly observed.

Neutron Stars

• Composed entirely of neutrons, which are subatomic particles lacking an electric charge.
• Formed as a result of a supernova explosion.
• Many neutron stars exhibit pulsar characteristics, displaying regular emissions of radio waves and X-rays.

Supernovae

• A stellar explosion marking the end of a star's life cycle.
• Responsible for creating most elements heavier than iron throughout the universe.

Red Giant Stars

• Evolved from main sequence stars into larger, cooler, and redder stars.
• At the conclusion of their life cycle, smaller red giants eject outer layers, forming a planetary nebula with a remaining carbon-oxygen core that becomes a white dwarf.

Binary Stars

• Systems of two stars that orbit a common center of mass.
• Up to 50% of all stars in the universe may be part of binary systems.

Medium Mass Stars (like the Sun)

• Sustain life by converting hydrogen in their cores into helium through nuclear fusion.
• Exhaust their hydrogen supply, leading to their eventual demise.

Nebulae

• Interstellar clouds composed of dust and plasma, often referred to as stellar nurseries.
• Serve as the birthplaces of new stars, originating from these clouds.