astronomical unit

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astronomical unit

(AU), mean distance between the earth and sun; one AU is c.92,960,000 mi (149,604,970 km). The astronomical unit is the principal unit of measurement within the solar system, e.g., Mercury is just over 1-3 AU and Pluto is about 39 AU from the sun.

astronomical unit

(AU or au) A unit of length that is used for distances, especially within the Solar System. It is effectively the mean distance between Earth and Sun. It is defined formally in terms of Kepler's third law and the Gaussian gravitational constant. One astronomical unit is equal to 149 597 870 kilometers or 499.005 light-seconds.

astronomical unit

[‚as·trə′näm·ə·kəl ′yü·nət]
(astronomy)
Abbreviated AU.
A measure for distance within the solar system equal to the mean distance between earth and sun, that is, about 92,956,000 miles (149,598,000 kilometers).
The semimajor axis of the elliptical orbit of earth.

astronomical unit

a unit of distance used in astronomy equal to the mean distance between the earth and the sun. 1 astronomical unit is equivalent to 1.495 × 1011 metres or about 9.3 × 107 miles
References in periodicals archive ?
The fourth star lies at a distance of 23 astronomical units from the planet.
Trujillo and Sheppard estimated that a planet about two to 15 times as massive as Earth, at a distance of 250 astronomical units (about eight times as far from the sun as Neptune) could explain why these 12 perihelia were bunched together.
These coziest of stellar companions are between zero and three astronomical units apart.
Counting these objects might ultimately reveal whether Neptune took roughly 1 million or 10 million years to migrate about 7 astronomical units from its birth site.
Paul Kalas (University of California, Berkeley), Abhijith Rajan (Arizona State University), and colleagues explored the super-Jupiter orbiting 650 astronomical units from the star HD 106906--more than 10 times Pluto's farthest point from the Sun.
5 astronomical units (AU, the distance from the Sun to the Earth) of the Sun, stripping a lot of material from the region and essentially starving Mars of formation materials.
The IBEX ribbon, which was recorded at energies from 200 to 6,000 electron volts, lies between about 100 and 125 astronomical units from the sun, McComas notes.
The disk spans somewhere between 760 and 980 astronomical units.
With an orbital distance of 8 to 15 astronomical units (AU), a Pictoris b is the closest exoplanet to its star that has ever been imaged.
A bull's-eye disk of dust and gas surrounds the young star HL Tauri, with ringlike gaps 15, 30, and 70 astronomical units from the star.
02 astronomical units (AU) when Mercury, the closest planet to the Sun, is at 0.
The outermost parts of such disks wouldn't contain enough material to assemble a Jupiter-mass planet at the distance from the star--330 astronomical units, or 330 times the separation between Earth and the sun--at which the team found the faint object.