Earth and Environmental Science ~ Unit 7, Module 23 Vocab

Photosphere

The innermost layer of the Sun’s atmosphere.

Chromosphere

The middle layer of the Sun’s atmosphere.

Prominence

An arc of gas ejected from the chromosphere, or gas that condenses in the Sun’s inner corona and rains back to the surface associated with sunspots.

Corona

The outermost layer of the Sun’s atmosphere.

Solar Flare

Violent eruptions of particles and radiation from the surface of the Sun.

Fusion

The combination of lightweight atomic nuclei into heavier nuclei.

Solar Wind

Streams of plasma flow outward from the corona at high speeds and form the solar wind.

Fission

The splitting of heavy atomic nuclei into smaller, lighter nuclei. (Opposite of Fusion)

Sunspot

A dark spot on the surface of the photosphere.

• It typically lasts a few days

• Sunspots occur in pairs

• Caused by magnetic fields.

Magnetic Field

The portion of space near a magnetic or current-carrying body where magnetic forces can be detected.

Constellation

Groups of stars that resemble animals, mythological characters, or everyday objects.

Binary Star

Two stars gravitationally bound together and orbit a common center of mass.

Luminosity

The energy output from the surface of a star per second.

Parsec

3.26 ly, or 3.086 × 1013 km.

Absolute Magnitude

how bright a star would appear if it were placed at a distance of 10 pc.

Hertzsprung-Russell diagram (H-R diagram)

A single graph that relates stellar characteristics— class, mass, temperature, diameter, and luminosity.

Parallax

The apparent shift in position caused by the motion of an observer.

Main Sequence

Most stars occupy the region in the diagram called the main sequence.

Apparent Magnitude

How bright the stars and planets appear in the sky from Earth.

Wavelength

The distance from one point on a wave to the next corresponding point.

Nebula

A cloud of interstellar gas and dust.

Protostar

Arotating disk-shaped mass with a hot, condensed object at the center.

Neutron Star

A collapsed, dense core of a star that forms quickly while its outer layers are falling inward.

Pulsar

A spinning neutron star that exhibits a pulsing pattern.

Supernova

When the outer layers of a star collapse into the neutron core, the central mass of neutrons creates a pressure, causing the central mass to explode outward as a supernova, leaving a neutron star.

Black Hole

A small, extremely dense remnant of a star whose gravity is so immense that not even light can escape its gravity field.

Evolution

A radical change in composition over a star’s lifetime.