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Solar radius is a unit of distance used to express the size of stars in astronomy relative to the Sun. The solar radius is usually defined as the radius to the layer in the Sun's photosphere where the optical depth equals 2/3:
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The barycentric celestial reference system (BCRS) is a coordinate system used in astrometry to specify the location and motions of astronomical objects. It was created in 2000 by the International Astronomical Union (IAU) to be the global standard reference system for objects located outside the gravitational vicinity of Earth: planets, moons, and other Solar System bodies, stars and other objects in the Milky Way galaxy, and extra-galactic objects.
References
- ↑ SOFA Software License for Issue 2009-02-01, International Astronomical Union, 2008-09-30, archived from the original on 2009-06-01, retrieved 2009-09-09.
- ↑ SOFA Software License for Issue 2008-03-01, International Astronomical Union, 2007-05-21, retrieved 2009-09-09[ permanent dead link ].
