Peri apsis: It is the closest approach point between two orbiting objects. Is combination of two words, parallax and second. ~: It is the distance at which a star would show a parallax shift of exactly one arcsecond as observed from Earth's orbit. One ~ is therefore about 31,000 billion km (19,180 billion miles), or 3.2616 light years, or 206,265 AU. It is defined as the distance at which one AU would look one arc second wide.
#DEFINE PARSEC PROFESSIONAL#
The measure of distance used by professional astronomers. The main body of the Space Shuttle where the payload, or cargo, is stored. Ī ~ is a unit of distance commonly used in astronomy and cosmology, the ~ is equal to about 3.262 light years, or 3.09 x 1016 metres. ~ - a unit of distance equal to about 3.25 light years or 19 trillion miles (31 trillion kilometers) a ~ is defined as the distance at which a celestial object exhibits a parallax shift of 1 arc-second when viewed from two different positions separated by the perpendicular distance of 1 Astronomical Unit. This is not defined for a circular orbit ( eccentricity = 0).
Periastron: The point in a binary orbit when the stars are closest tog ether. ~: The distance at which an object has a trigonometric parallax of one second of arc, or 3 x 1018 cm. It's about the angle a 10 cent coin makes when it's over 4.5 km away. ~ - the distance at which one astronomical unit (the distance between Earth and the Sun, about 150,000 km) subtends an arc of one arcsecond (¹/3600°). The length of time between successive peaks in the brightness of a variable star. Approximately 3.26 light years or 32 million million km. The distance at which a star would have a parallax angle of 1". ~-scale dust distributions in Seyfert galaxies - Results of the MIDI AGN snapshot survey p. Penumbra - During an eclipse, the area of partial shadow. Partial eclipse - When the moon partially blocks the sun or the Earth's shadow partially the Moon. ~ - A unit of distance equal to 3.26 light-years, and the the distance at which a star would have a parallax of 1 second of arc. Pair production The process in which two photons of electromagnetic radiation give rise to a particle-anti-particle pair. ~ The distance at which a star must lie in order that its measured parallax is exactly 1 arc second, equal to 206,000 A.U. A ~ is the distance at which 1 AU subtends an angle of 1 arcsec. This is because its definition is closely related to a method of measuring the distances between stars. Many astronomers prefer to use ~s (abbreviated pc) to measure distance to stars. The use of the ~ has been carried into the 21st Century because of historical inertia and because its use avoids the application of conversion factors - i.e., 3.Ī ~ is a unit of length used to measure the distances between objects located beyond our solar system, and is equal to 3.26 light-years (19 trillion miles/31 trillion km). The radius of the Earth's orbit equals one astronomical unit (AU), so an object that is one ~ distant is 206,265 AU (or 3.26 light-years) away. One ~ is the distance to an object whose parallax angle is one arcsecond. Unit of distance at which a star would have a parallax of 1 second of arc from a planet of exactly 1 astronomical unit (AU) distance from its primary. A ~ is equal to about 3.26 light-years (31 trillion kilometres or 19 trillion miles) in length.Ī ~ is the unit for expressing distances to stars and galaxies, used by professional astronomers. One ~ is the distance at which one astronomical unit subtends an angle of one arcsecond. Ī parsec is defined as the distance from the Sun which would result in a parallax of 1 second of arc as seen from Earth.Ī ~ (symbol: pc) is a unit of length used to measure large distances to objects outside the Solar System. The parsec was defined to be the distance at which 1 AU (perpendicular to the line of sight) subtends an angle of 1 arcsecond. Distances to the closest stars can be determined through measurement of their trigonometric parallax.