The corona of a star is a large, white halo of glowing gas. A stellar wind is a constant stream of sub-atomic particles moving at faster than the escape velocity of the star's gravitational field. They escape through windows in the corona, called coronal holes, regions where the magnetic fields are weak and the charged stellar wind particles are not trapped in magnetic bottles. X-ray and UV pictures of the corona show that the hot gas is connected to the magnetic features in the photosphere. Those low level structures extending into long streamers in the outer corona and heat the corona to its million degree temperatures.
Gases normally obey the Ideal Gas Law.
However, when the atoms become very densely packed, special rules of quantum mechanics control the behavior of the atoms. In particular, the Pauli exclusion principle limits the number of particles of a given kind that can be put into a cubic centimeter of space. When the density of the gas reaches this limit it begins to behave like a liquid. For normal gases, when the density or temperature go up, the pressure goes up. For extremely high density gases, the pressure becomes almost independent of temperature and the gas is said to be degenerate .