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"
The Astrosphere of HD 61005
06/03/2026
Do young stars blow bubbles? The larger view shows a stellar field observed with the Cerro Tololo Inter-American Observatory in Chile, and the inset highlights HD 61005, a star like our Sun, only 120 light-years away. Much younger than the Sun, at just about 100 million years old, it blows a fast and dense stellar wind that pushes out the cooler dust and gas that surrounds it, forming a bubble called an astrosphere. The star-blown bubble was detected with the Chandra X-ray Observatory, and it has a diameter roughly 200 times the Earth-Sun distance. Our Sun has a bubble too, called the heliosphere, which protects the planets from cosmic radiation. Also shown in the inset is debris left behind from star formation, observed by Hubble. The debris appears as wings, giving the star its nickname: the Moth.