Astronomers analyze the composition of the photosphere with a spectrograph and telescope in order to model the interior of the star. A hot, ionized gas. Energetic photons strip electrons from atoms, which results in a hot soup of free electrons and ionized atoms. The Sun is mostly hydrogen plasma. One complete wobble takes 26,000 years.
Precession changes the pole star as seen from Earth.
Thuban was the pole star while the Egyptians built the Pyramids in Egypt. The motion of precession rotated the Earth's axis away from Thuban towards Polaris. 13,000 years from now, Earth's rotational axis will point at Vega. A reflecting telescope's primary mirror focal point. Astronomers place cameras at prime focus to record bright, wide field images.