This is hot enough to emit black-body radiation in the X-ray spectrum.

In 1894 Planck turned his attention to the problem of black-body radiation.

Wien proceeded to study the characteristics of this black-body radiation.

Planck's law of black-body radiation follows immediately as a geometric sum.

The most common light sources are thermal: a body at a given temperature emits a characteristic spectrum of black-body radiation.

He also formulated an expression for the black-body radiation which is correct in the photon-gas limit.

If you remember your black-body radiation, black is actually best in heat.

The colour of simple incandescence is due to black-body radiation.

The radiation of such perfect emitters is called black-body radiation.

With all these assumptions in place, the star emits black-body radiation at the temperature of the photosphere.