Stellar Parallax and Angular Measurement in Astrophysics

These flashcards focus on key vocabulary and concepts related to stellar parallax and measurement techniques in modern astrophysics.

Stellar Parallax

The apparent shift in position of a star against a distant background due to Earth's movement.

Angular Size

The apparent size of an object in the night sky, measured in degrees, arcminutes, or arcseconds.

Arcminute

A unit of angular measurement equal to 1/60th of a degree.

Arcsecond

A unit of angular measurement equal to 1/60th of an arcminute.

Parsec

A unit of distance used in astronomy, equivalent to about 3.26 light-years or 206,265 astronomical units.

Friedrich Bessel

A German astronomer who made the first successful measurement of stellar parallax in 1838.

Limitations of Stellar Parallax

Challenges in measuring parallax angles less than 0.01 arcseconds, mainly due to atmospheric interference.

GAIA

A modern space-based telescope project intended to measure the positions and distances of over a billion stars.

Hipparcos

A satellite that performed a high-precision parallax measurement of stars from 1989 to 1993.

Mean Apex

The average point in the sky towards which the solar system is moving, often used in measurements over time.