Astronomers discover eight new super-hot stars
A sky survey image centred on the newly-discovered O(H) star SALT J203959.5-034117 (J2039). Credit: Tom Watts (AOP), STScINASA, The Dark Energy Survey, Licence type Attribution (CC BY 4.0)

Eight of the hottest stars in the universe were discovered by an international team of astronomer. The work was published in a monthly publication.

The paper is based on data gathered using the Southern African Large Telescope. The study describes how a survey of subdwarf stars led to the discovery of several very hot white dwarfs and pre-white dwarf stars. The sun's surface is less than 6000 degrees.

The central star of the planetary nebula is one light year in diameter. There are two "variable" stars. All of these stars are nearing the end of their lives and are white dwarfs. Each of the new discoveries is more than one hundred times brighter than the sun, which is atypical for white dwarf stars.

White dwarfs are a million times larger than Earth and have the same mass. They are the most dense stars in existence. Within a few thousand years, pre-white dwarfs will become white dwarfs.

A star with an effective temperature of 100,000 degrees Celsius or higher is extremely rare. Our survey found a lot of these stars. The discoveries will help to increase our understanding of the late stages of stellar evolution, and they show that SALT is a great telescope for our project. The discovery of the stars, the analysis of their atmospheres, and the discovery of pulsations and a nebula in a very short space of time have been accomplished with the help of an experienced team.

The University of Tuebingen's Professor Klaus Werner is proud to have helped develop the paper. We hope that the discovery of eight very hot white dwarf and pre-white dwarf stars and a new planetary nebula will shed new light on the formation of our galaxy.

It is an honor to have been involved in the discovery, says Dr. Itumeleng Monageng, of the Department of Astronomy, University of Cape Town. The survey of hot subdwarfs was intended to explore evolutionary pathways.

There are eight new extremely hot stars, one of which is surrounded by a planetary nebula.

There are hot white dwarfs and pre-white dwarfs found with SALT. 10.093/mnras/stac3531

Journal information: Monthly Notices of the Royal Astronomical Society