coronal bright point
One of the three key features of the Sun when seen in X-rays, the others being active regions and coronal holes. Unlike active regions, coronal bright points are distributed at all latitudes on the solar disk. Bright points have a central core around 10 000 km wide and mostly occur above areas of opposite magnetic polarity on the photosphere; when the regions of opposite polarity encounter each other and cancel out, energy is released that heats the gas above the photosphere to 1–2 million K. Bright points also occur when newly emerged magnetic field reacts with the pre-existing magnetic field in the corona, again with the release of magnetic energy to heat the gas. Coronal bright points have typical lifetimes of a day. They are often referred to as X-ray bright points or EUV bright points, according to the wavelength at which they are observed.