The amount of heat required to raise the temperature of a unit mass of Frozen Ground by one degree Celsius/Kelvin. Because the phase change in Frozen Ground often occurs gradually over a range of temp
eratures, the Apparent Heat Capacity (which is the sum of the Specific Heat Capacity and the Latent Heat released) may vary significantly with temperature.
A measure of a star's observed brightness (opposed to absolute magnitude); symbol m. It depends on the star's intrinsic brightness, its distance from the observer, and the amount of interstellar absor
ption. The brightest star Sirius has an apparent magnitude of -1.46, while the weakest stars visible with the naked eye in the most favorable observation conditions have magnitudes of about +6.5. The stars of magnitudes less than +23 are measured by professional observatories, whereas those of magnitudes less than +30 by a telescope such as the Hubble Space Telescope.
A position given by the coordinates calculated for a star, if it were seen from the Earth's center, relative to the real equator and the real equinox, at a certain date. It includes the displacements
from one heliocentric direction, given in a stellar catalogue, due to precession, nutation, aberration, proper motions, annual parallax, and light gravitational deviation.