| tangential (transverse) velocity |
The component of a star's space velocity that lies in
the plane of the sky. |
| temperature |
A measure of how fast the particles in a body are moving
or vibrating in place; a measure of the average heat energy in a body. |
| temperature (Celsius; formerly centigrade) |
Temperature measured on scale where water freezes at
0 degrees and boils at 100 degrees. |
| temperature (color) |
The temperature of a star as estimated from the intensity
of the stellar radiation at two or more colors or wavelengths. |
| temperature
(effective) |
The temperature of a blackbody that would radiate the
same total amount of energy that a particular object, such as a star, does. |
| temperature (excitation) |
The temperature of a star as estimated from the relative
strengths of lines in its spectrum that originate from atoms in different
stages of excitation. |
| temperature (Fahrenheit) |
Temperature measured on a scale where water freezes
at 32 degrees and boils at 212 degrees. |
| temperature (ionization) |
The temperature of a star as estimated from the relative
strengths of lines in its spectrum that originate from atoms in different
stages of ionization. |
| temperature (Kelvin) |
Absolute temperature measured in Celsius degrees, with
the zero point at absolute zero. |
| terrestrial planet |
Any of the planets Mercury, Venus, Earth, or Mars; sometimes
the Moon or Pluto are included in the list. |
| theory |
A set of hypotheses and laws that have been well demonstrated
to apply to a wide range of phenomena associated with a particular subject. |
| thermal equilibrium |
A balance between the input and outflow of heat in a
system. |
| thermal radiation |
The radiation emitted by any body or gas that is not
at absolute zero. |
| transition region |
The region in the Sun's atmosphere where the temperature
rises very rapidly from the relatively low temperatures that characterize
the chromosphere to the high temperatures of the corona. |
| triple-alpha process |
A series of two nuclear reactions by which three helium
nuclei are built up into one carbon nucleus. |
| Tropic of Cancer |
The parallel (circle) of latitude 23.50 N. |
| Tropic of Capricorn |
The parallel (circle) of latitude 23.5' S. |
