That is, if you observe the spectrum of a star and can determine the wavelength where the emission peaks (Î»max), you can calculate that starâs temperature. Here is another copy of the plot that we studied in Lesson 3: Figure 4.1: Two-dimensional plot of the spectrum of a blackbody with different temperatures.
Igneous rocks usually contain the most crystals. The longer it takes the magma to cool, the larger the crystals.
This produces a rock with two different crystal sizes: large crystals that formed slowly at depth (known as phenocrysts), and small crystals that formed quickly at the surface (known as groundmass). Andesite porphyry is the name used for these rocks with two crystal sizes.