The Sun
The Sun is a yellow dwarf star (G2V), about 4.6 billion years old, and the dominant gravitational force in the Solar System. It has a diameter of roughly 1.4 million kilometers and contains around 99.8% of the Solar System’s mass. Nuclear fusion in its core converts hydrogen into helium, producing energy that warms the planets. Above the core lie the radiative and convective zones, followed by the visible photosphere (~5,500 °C), the chromosphere, and the much hotter corona (~2 million °C).
Source: science.nasa.gov
APODs including "The Sun"
Dust, Gas, and Stars in the Orion Nebula
08/03/2017
The Great Nebula in Orion, an immense, nearby starbirth region, is probably the most famous of all astronomical nebulas. Here, filaments of dark dust and glowing gas surround hot young stars at the edge of an immense interstellar molecular cloud only 1500 light-years away. In the featured deep image shown in assigned colors, part of the nebula's center is shown as taken by the Hubble Space Telescope. The Great Nebula in Orion can be found with the unaided eye near the easily identifiable belt of three stars in the popular constellation Orion. In addition to housing a bright open cluster of stars known as the Trapezium, the Orion Nebula contains many stellar nurseries. These nurseries contain much hydrogen gas, hot young stars, proplyds, and stellar jets spewing material at high speeds. Also known as M42 and M43, the Orion Nebula spans about 40 light years and is located in the same spiral arm of our Galaxy as the Sun.