Untitled Flashcards Set

Mare

Dark, basaltic plains on the Moon, formed by ancient volcanic eruptions.

Highlands

Light-colored, mountainous regions on the Moon, made up of lunar crust.

Central Peak

A peak that rises from the center of a lunar impact crater, formed by the rebound of the surface.

Rilles

Long, narrow depressions on the lunar surface, believed to be formed by ancient lava flows.

Crater Age Identification

Older craters are often found beneath younger craters and tend to be generally larger.

Phases of the Moon

The cyclical appearance of the Moon, which includes New Moon, First Quarter, Full Moon, and Last Quarter.

Terminator Line

The dividing line between the illuminated and dark sides of the Moon.

Photosphere

The visible surface layer of the Sun, from which light is emitted.

Chromosphere

A layer of the Sun's atmosphere above the photosphere, characterized by a reddish glow.

Sunspots

Dark spots on the Sun's surface caused by intense magnetic activity.

Sunspot Cycle

The approximately 10-year cycle of increase and decrease in sunspot activity.

Coronal Mass Ejections

Massive bursts of solar wind and magnetic fields rising above the solar corona.

Solar Flares

Intense bursts of radiation from the Sun's surface, associated with sunspots.

Corona Temperature

The outer atmosphere of the Sun, hotter than the chromosphere due to magnetic loops releasing energy.

Angular Size (θ) Relation

The relationship between angular size and distance, described by D = S / θ in radians.

Conversion of Degrees to Radians

To convert degrees to radians, use the formula: radians = degrees × (π / 180).

Distance Calculation in Parsecs and AU

The distance to an object in parsecs is related to its angular size using Dpc = 1/θ in degrees.

Astronomical Unit in km

1 Astronomical Unit (AU) is approximately 1.5 × 10^8 km.

Apparent Magnitude (m)

A measure of a star's brightness as seen from Earth, influenced by distance.

Absolute Magnitude (M)

A measure of a star's intrinsic brightness, standardized to a distance of 10 parsecs.

Brightness Inference

A more positive value of Absolute Magnitude (M) indicates lesser brightness for a star.

Distance to Stars Calculation

Distance in parsecs to a star is calculated as Dpc = 10|m - M / 5 + 1|.

Energy Calculation of a Star

Energy factor is calculated using E = (2.512)^(Ma - Mb).

Relative Size of Stars

The relative size of two stars can be compared using Ra/Rb = Energy factor (E).

H-R Diagram Significance

The Hertzsprung-Russell diagram shows the relationship between a star's brightness and age.

Absolute vs Apparent Magnitude

Absolute Magnitude is preferred as it provides an intrinsic measure of brightness, irrespective of distance.