Using a massive telescope in South Africa, an international research team has discovered eight of the hottest stars in the universe. The surface temperature of each of the celestial bodies is more than 100,000 degrees. By comparison, the sun’s surface reaches “only” about 5,800 degrees.
The team, led by Simon Jeffrey of the Armagh Observatory in Northern Ireland and including Klaus Werner of the Institute of Astronomy and Astrophysics at the University of Tübingen, had studied data from so-called subdwarfs. This is the name given to stars that evolve into white dwarfs. “White dwarfs are about the size of the Earth, but a million times more massive. They are the densest stars in existence that are made of normal matter,” Werner explained.
Both subdwarfs and white dwarfs could have high surface temperatures. “Of the eight super-hot stars we discovered, the hottest was a white dwarf with a surface temperature of 180,000 degrees.”
A hundred times as bright as the sun
According to astrophysicist Werner, each of the stars shines more than a hundred times as brightly as the sun. However, he said, they are all located between 1,500 and 22,000 light-years from Earth, while the sun is only a little more than eight light-minutes away. Thus, the hot, bright dwarfs could not be seen by Earth’s naked eye. A light year refers to the distance light travels within a year.
Despite the distance, the discovery is important to the experts: “The results could also shed new light on the formation of our galaxy,” Werner explained. The results were published in the journal Monthly Notices of the Royal Astronomical Society. The measurements were made with the Southern African Large Telescope (SALT), located about 400 kilometres northeast of Cape Town.