Hot white dwarfs and pre-white dwarfs discovered with SALT, MNRAS

  • B
  • Thread starter Astronuc
  • Start date
  • Tags
    Hot Salt
In summary, an international team of astronomers used the Southern African Large Telescope to discover eight of the hottest stars in the universe, with surfaces hotter than 100,000 degrees Celsius. These stars, including the central star of a newly discovered planetary nebula and two pulsating stars, are at an advanced stage of their life cycle and are approaching the end of their lives as white dwarfs. They are more than 100 times brighter than the sun, and their high temperatures may be due to recently being liberated from their AGB star or merging with another white dwarf. The findings were published in Monthly Notices of the Royal Astronomical Society and the study can be found in the link provided.
  • #1
Astronuc
Staff Emeritus
Science Advisor
2023 Award
21,870
6,271
An international team of astronomers has discovered eight of the hottest stars in the universe, all with surfaces hotter than 100,000 degrees Celsius. The work was published in Monthly Notices of the Royal Astronomical Society.

The paper is based on data gathered using the Southern African Large Telescope (SALT), the largest single optical telescope in the southern hemisphere, with a 10m x 11m mirror. The study describes how a survey of helium-rich subdwarf stars led to the discovery of several very hot white dwarf and pre-white dwarf stars, the hottest of which has a surface temperature of 180,000 degrees Celsius. For comparison, the sun's surface is a mere 5,800 degrees.
https://phys.org/news/2023-01-astronomers-super-hot-stars.html

One of the stars identified is the central star of a newly discovered planetary nebula, which is one light year in diameter. Two of the others are pulsating, or "variable" stars. All of these stars are at an advanced stage of their life cycle and are approaching the end of their lives as white dwarfs. Due to their extremely high temperatures, each of these new discoveries is more than one hundred times brighter than the sun, which is considered unusual for white dwarf stars.

https://academic.oup.com/mnras/article/519/2/2321/6967306?login=false
 
  • Like
  • Informative
Likes berkeman, jedishrfu, Ibix and 1 other person
Astronomy news on Phys.org
  • #3
White dwarfs are very hot when first liberated from the AGB star that used to surround them, since they are what is left over from the hot stellar core. So one presumes these are recently liberated and have not yet had much time to cool. If they are older, it might be that they recently merged with another white dwarf, which could heat them up again.
 
  • Informative
Likes berkeman

1. What is SALT and how does it help in discovering hot white dwarfs and pre-white dwarfs?

SALT (Southern African Large Telescope) is a 10-meter class optical telescope located in South Africa. It uses a unique design with a fixed segmented primary mirror and a large field of view, making it ideal for wide-field surveys. SALT has been used to discover hot white dwarfs and pre-white dwarfs due to its sensitivity to faint objects and its ability to observe a large portion of the sky.

2. What are hot white dwarfs and pre-white dwarfs?

Hot white dwarfs are the cores of stars that have exhausted their nuclear fuel and have shed their outer layers. They are extremely hot, with temperatures reaching up to 100,000 K. Pre-white dwarfs, on the other hand, are stars that are in the process of becoming white dwarfs. They are still burning hydrogen in their cores and are not as hot as white dwarfs, with temperatures typically between 5,000-10,000 K.

3. How are hot white dwarfs and pre-white dwarfs different from other types of stars?

Hot white dwarfs and pre-white dwarfs are different from other types of stars because they have exhausted their nuclear fuel and are no longer able to produce energy through nuclear fusion. They are also much smaller and denser than other stars, with white dwarfs having a mass similar to that of our Sun but a size comparable to Earth.

4. What can we learn from studying hot white dwarfs and pre-white dwarfs?

Studying hot white dwarfs and pre-white dwarfs can provide insight into the late stages of stellar evolution. These objects can also be used as probes to study the chemical composition and dynamics of the interstellar medium. Additionally, their properties can be used to test theories of stellar structure and evolution.

5. How many hot white dwarfs and pre-white dwarfs have been discovered with SALT?

As of 2021, over 100 hot white dwarfs and pre-white dwarfs have been discovered with SALT. These objects were found through various surveys, such as the SALT HRS (High Resolution Spectrograph) survey and the SALT HRS Southern CV Survey, which specifically target these types of stars.

Similar threads

  • Astronomy and Astrophysics
Replies
9
Views
1K
  • Astronomy and Astrophysics
Replies
6
Views
2K
Replies
2
Views
3K
  • Astronomy and Astrophysics
Replies
1
Views
3K
Replies
1
Views
6K
  • Introductory Physics Homework Help
Replies
23
Views
12K
  • MATLAB, Maple, Mathematica, LaTeX
Replies
1
Views
2K
  • Beyond the Standard Models
Replies
2
Views
2K
  • MATLAB, Maple, Mathematica, LaTeX
Replies
5
Views
2K
  • MATLAB, Maple, Mathematica, LaTeX
Replies
1
Views
2K
Back
Top