

The sun’s core reaches temperatures of 27 million degrees Fahrenheit (15 million degrees Celsius). Temperatures vary in different parts of the sun and its atmosphere. How hot is the sun?Īn illustration of the sun's layers. The larger a star is, the more rapidly it burns through its hydrogen content some of the largest stars - such as those with masses 40 times that of the sun - have lifetimes as short as a million years compared to the Sun's main-sequence lifetime of around 10 billion years, according to Swinburne University of Technology in Australia (opens in new tab). The generations of stars that preceded the sun would have had smaller ratios of metals than this, enriching their galaxies with heavier elements upon their deaths. The ratio of the sun's mass is 73% hydrogen, 25% helium, and 2% metals. Like all main-sequence stars, the majority of the sun's mass is made up of hydrogen, with some helium and traces of heavier elements , which are referred to as the metallicity or “Z” of a star (the astronomical definition of a metal is "any element heavier than helium").

This is called the main sequence.īefore the main sequence stars like the sun exist as what is known as protostars, gathering mass from their surroundings and growing to the mass required to initiate fusion. The difference in mass between the hydrogen atoms and the daughter helium atom is released as energy - the heat and light that sustain our planet. The sun is in the period of a stellar body's life in which it fuses hydrogen to create helium. (Image credit: NASA/Johns Hopkins APL/Steve Gribben) An artist's concept of the sun being observed by NASA's Parker Solar Probe.
