Astrophysics (index)about

surface temperature

(temperature of the surface of a star or planet)

The term surface temperature is used in astronomy for stars an planets.

In the case of stars, the effective temperature is generally used/quoted as the surface temperature. In fact, the exact location of the surface of a star is located is unclear as the star is gas or plasma and beyond the star is additional gas/plasma. The surface is generally taken as what appears to us to be the outside of the star, i.e., that part which produces the light we see, a layer of the star called the photosphere. As opposed to the center or deeper regions of the star, the photosphere is the portion whose temperature determines the spectrum and therefore color of the star. The photosphere has a some depth and the emerging light comes from a range of depths at a range of temperatures. The effective temperature is a relatively easy-to-determine quantity used to approximate this temperature range. Spectral lines, whose form and magnitude depend on temperature, can be used to determine more accurately the photosphere's temperature at different depths.

For planets, the surface temperature is more defined, especially for rocky planets. The reflection of electromagnetic radiation means the observed spectrum does not reflect surface temperature, so other means are required, including determining the black body contribution of the spectrum, and investigating the temperature of the atmosphere through analysis of spectral lines.


Referenced by:
A-type star (A)
B-type star (B)
equilibrium temperature (Teq)
F-type star (F)
G-type star (G)
greenhouse effect
K-type star (K)
L-type star (L)
M-type star (M)
O5 spectral class (O5)
O-type star (O)
red clump (RC)
red dwarf
spectral class
stellar temperature determination
T-type star (T)
Y-type star (Y)