Since you've not provided any clues... It could be - ight year, parsec or astronomical unit
stellar parallax
Stellar Collision Theory: The coming together of two astronomical bodies (stars), which through the force of gravity, merge into one larger unit
The average distance of a planet to the sun is the Semi-major axis. The furthest it gets is the Aphelion and the closest it gets is its Perihelion. The Sun to Earth Distance is also known as one Astronomical Unit (AU).
The distance from the earth to the sun is called an astronomical unit. 1 Astronomical Unit = 4.90807087 × 1011 feet
A light-year is a unit of distance, not a unit of time.
Light year is used to measure the stellar distances whereas miles and km is used to measure distance on Earth.
stellar parallax
Since it is so close you would use stellar parallax to resolve the distance to proxima centauri.
Stellar distances are measured in light-years, which is the average distance between the Earth and the Sun.
A light year
stellar parralax
Stellar Collision Theory: The coming together of two astronomical bodies (stars), which through the force of gravity, merge into one larger unit
metre
The most common is the light year, which is the distance that a beam of light will travel in one year, and is approximately 10 trillion kilometres (or about 6 trillion miles).Another unit of inter-stellar measurement is the parsec. One parsec is equal to about 3.26 light years (31 trillion kilometres, or 19 trillion miles).
The S.I. unit of distance is the metres, which is basically the distance between any two points.
A meter does not have weight - it is a unit of distance.
Distance is the unit of length.In Physics, 1 unit of distance is 1 unit of speed into 1 unit of time.That means 1 km distance is equal to 1 km/h of speed of the object in 1 hr of time . Distance=speed *time.