8 new super-hot stars
The Royal Astronomical Society, based mostly in London, stated this week (January 9, 2023) that astronomers have pinpointed eight of the most popular stars but identified 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 solar, 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 challenge. You’ll discover the preprint online here.
The astronomers had been utilizing the Southern African Giant 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 solar. Additionally, they’re a lot dimmer than common O-type main-sequence stars, that are younger and really large stars. Actually, one idea about helium-rich subdwarfs is that – as an alternative of being younger – they’re developed stars, of a kind generally known as white dwarfs.
They’re white dwarf stars
Finally, our solar will change into a planet-sized white dwarf star, billions of years from now. That’ll be after the solar’s inner thermonuclear furnace consumes the hydrogen within the solar’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 types of stars, the core of the star is considered surrounded by a shell through which helium (the 2nd-most-complex factor after hydrogen) is burning. And astronomers imagine 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 anticipate finding a white dwarf. It seems to be the central star of a newly found planetary nebula, which is an unlimited shell of fuel round an developed star, fashioned from the layers of fuel which have sloughed off the star. This super-hot star’s planetary nebula seems to be a couple of light-year large.
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 result of their extraordinarily excessive temperatures, every of those new discoveries is a couple of hundred occasions brighter than the solar, which is taken into account uncommon for white dwarf stars.
Shedding gentle on how stars evolve
The very fact is, white dwarfs are the densest stars in existence that include regular matter. And pre-white dwarfs are just a few occasions greater and can shrink to change into 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 increased 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 global crew 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
