8 new super-hot stars
The Royal Astronomical Society, primarily based in London, stated this week (January 9, 2023) that astronomers have pinpointed eight of the most popular stars but recognized in our universe. Surprisingly, all have surfaces hotter than 100,000 levels Celsius (180,000 F). And the most popular has a floor temperature of 180,000 C! That’s in distinction to our sun, which has a floor temperature of about 5,800 C (10,500 F).
The Month-to-month Notices of the Royal Astronomical Society will publish the brand new work in its February 2023 subject. You’ll discover the preprint online here.
The astronomers had been utilizing the Southern African Massive Telescope (SALT) to survey helium-rich subdwarf stars. What’s extra, these are scorching, low-mass stars, thought to have a mass roughly half that of our sun. Additionally, they’re a lot dimmer than common O-type main-sequence stars, that are younger and really large stars. Actually, one principle about helium-rich subdwarfs is that – as a substitute of being younger – they’re advanced stars, of a sort often known as white dwarfs.
They’re white dwarf stars
Finally, our sun will turn out to be a planet-sized white dwarf star, billions of years from now. That’ll be after the sun’s inside thermonuclear furnace consumes the hydrogen within the sun’s core. That’s as a result of helium-rich subdwarfs are thought to have cores of carbon and oxygen, that are by-products of thermonuclear burning. So in these kinds of stars, the core of the star is considered surrounded by a shell during which helium (the 2nd-most-complex component after hydrogen) is burning. And astronomers consider helium-rich subdwarfs include between 50 to 100% helium, as evidenced by their spectra.
One of many newly recognized super-hot stars is in a spot the place you’ll certainly look forward to finding a white dwarf. It seems to be the central star of a newly found planetary nebula, which is an unlimited shell of gasoline round an advanced star, fashioned from the layers of gasoline which have sloughed off the star. This super-hot star’s planetary nebula seems to be a few light-year broad.
2 of the 8 are variable stars
Moreover, two of the opposite newly found scorching stars are pulsating stars, or variable stars.
The astronomers’ assertion defined:
All of those stars are at a complicated stage of their life cycle and are approaching the tip of their lives as white dwarfs. As a consequence of their extraordinarily excessive temperatures, every of those new discoveries is a couple of hundred instances brighter than the sun, which is taken into account uncommon for white dwarf stars.
Shedding gentle on how stars evolve
The actual fact is, white dwarfs are the densest stars in existence that include regular matter. And pre-white dwarfs are just a few instances greater and can shrink to turn out to be white dwarfs inside just a few thousand years.
Simon Jeffery, an astronomer on the Armagh Observatory and Planetarium, who led the analysis, stated:
Stars with efficient temperatures of 100,000 levels Celsius or greater are extremely uncommon. It was an actual shock to search out so many of those stars in our survey. These discoveries will assist to extend our understanding of the late phases of stellar evolution.
Backside line: A world staff of astronomers – utilizing a telescope in South Africa – have found 8 new super-hot stars.
Source: Hot white dwarfs and pre-white dwarfs discovered with SALT
