University Of Tübingen Expert Astronomers Discover Eight Super-Hot Stars

Using the largest single telescope in the southern hemisphere, the SALT in South Africa, an international team of astronomers has discovered eight of the hottest stars in the universe. Its surface temperature is more than 100,000 degrees – the surface of the sun only reaches 5,800 degrees. The discoveries came from a research project led by Professor Simon Jeffrey of the Armagh Observatory in Northern Ireland, and involving Professor Klaus Werner of the Institute for Astronomy and Astrophysics at the University of Tübingen. The results were published in the journal Monthly Notices of the Royal Astronomical Society .

The Southern African Large Telescope (SALT) is located around 400 kilometers northeast of Cape Town. Researchers examined data obtained from surveys of helium-rich hot subdwarfs using this telescope. In astronomy, subdwarfs are stars that develop into white dwarfs. “White dwarfs are roughly the size of Earth, but a million times more massive. They are the densest existing stars made of normal matter. Their direct predecessors, the so-called sub-dwarfs, are somewhat larger. They contract and become white dwarfs within a few thousand years,” explains Klaus Werner. “Both hot subdwarfs and white dwarfs can have high surface temperatures. Of the eight super hot stars we’ve discovered,

Previously unknown planetary nebula
According to Werner, each of the newly discovered stars is more than a hundred times brighter than the sun. However, unlike the Sun, which is just over eight light-minutes away, they are between 1,500 and 22,000 light-years from Earth and therefore cannot be seen with the naked eye. One of the stars found is the central star of a newly discovered planetary nebula, one light-year in diameter. Two of the other objects are oscillating stars. “All of these stars are in a very advanced stage of their life cycle and are nearing extinction as white dwarfs,” says Werner, adding: “I am proud to have helped initiate this groundbreaking research. The results could also shed new light on the formation of our galaxy.”

The co-author of the study Dr. Itumeleng Monageng from the University of Cape Town and the South African Astronomical Observatory , operator of the SALT telescope, says: “The purpose of the SALT survey of helium-rich hot subdwarfs was to explore the evolutionary paths of different types of stars in their late stages. The discovery of extremely hot stars surprised us.” Simon Jeffery explains that stars with temperatures of 100,000 degrees or more are extremely rare. “It was also surprising that so many such objects were found in our sky survey. These discoveries will help to better understand late stages of stellar evolution. They also demonstrate that SALT is a great telescope for our project.”