Astronomers utilizing the Very Giant Telescope of the European Southern Observatory (ESO) have discovered a metallic “scar” on the floor of a white dwarf star. This video – by ESO – summarizes the invention.
- When sunlike stars die, they swell into enormous red giant stars. Later, they collapse to turn into small, dense white dwarf stars. On this means of swelling then collapsing, they’ll devour or “cannibalize” their planets. Astronomers have seen metals scattered on white dwarf surfaces, presumably from long-gone planets.
- Now, for the primary time, astronomers have recognized a concentrated patch or scar on a white dwarf referred to as WD 0816-310.
- The scar on WD 0816-310 is situated on considered one of its magnetic poles, suggesting that its magnetic subject performed an important position within the course of throughout which the white dwarf “ate” its planet.
Steel scar on a cannibal star
Astronomers said on February 26, 2024, that they’ve discovered a “metallic” scar on a cannibal white dwarf star for the primary time.
Previous to this discovery, that they had discovered “metals” on white dwarf surfaces. Metals, in astronomy, means all the weather of the periodic table aside from hydrogen and helium. However that is the primary time they’ve discovered a literal scar on a star left by the cannibalization course of.
The scarred white dwarf’s designation is WD 0816-310. It’s situated 63 light-years from Earth. When it was youthful, it was doubtless a star very similar to our sun (though maybe extra huge). However when it started to age, the star swelled up right into a red giant star, simply as our sun will do. Its outer layers will need to have engulfed any close-orbiting planets. When our sun turns into a pink large, its outer layers will engulf Earth and probably Mars. Later, WD 0816-310 shrank down right into a tiny burned-out corpse of its former self, referred to as a white dwarf. Like most different identified white dwarfs, WD 0816-310 is extra huge than our sun, however solely concerning the measurement of Earth.
And now we see that this white dwarf star has a metallic scar (or “patch” because the scientific paper calls it).
These astronomers made their discovery utilizing the Very Giant Telescope (VLT) in Chile, which is operated by the European Southern Observatory (ESO).
The analysis group published their peer-reviewed ends in The Astrophysical Journal Letters on February 26.
Steel scar on white dwarf star
So astronomers had detected traces of metals on white dwarfs earlier than, even from what they’ve believed have been former Earth-sized planets. However that is the very first scar they’ve discovered.
Moreover, they are saying that the white dwarf’s magnetic subject will need to have been concerned in creating the scar. They consider this to be the case as a result of the scar is situated at one of many white dwarf’s magnetic poles. Stefano Bagnulo, lead creator and astronomer at Armagh Observatory and Planetarium in Northern Eire, U.Ok., said:
It’s well-known that some white dwarfs – slowly cooling embers of stars like our sun – are cannibalizing items of their planetary methods. Now we have now found that the star’s magnetic subject performs a key position on this course of, leading to a scar on the white dwarf’s floor.
Co-author Jay Farihi at College School London, U.Ok., defined:
We’ve demonstrated that these metals originate from a planetary fragment as giant as or probably bigger than Vesta, which is about 300 miles (500 km) throughout and the second-largest asteroid within the solar system.
How did the scar type?
Bagnulo and his colleagues used the FORS 2 instrument on the Very Giant Telescope to search out the scar. The astronomers discuss with it as a “Swiss Military knife,” able to varied sorts of observations. Bagnulo mentioned:
ESO has the distinctive mixture of capabilities wanted to watch faint objects equivalent to white dwarfs, and sensitively measure stellar magnetic fields.
The researchers discovered the scar by first noticing that the quantity of metallic detected diversified because the white dwarf rotated. The metals have been concentrated in a single area as an alternative of being unfold out. One other clue got here from how the focus of metals was synchronized with the white dwarf’s magnetic subject. The scar is on one of many white dwarf’s magnetic poles. The researchers mentioned which means that the magnetic subject ionized and “funneled” the metals from the previous planet onto the magnetic poles of the white dwarf. Thus, the formation of the scar. The method can be just like how auroras form on Earth and on Jupiter.
That is an artist’s animation of the white dwarf WD 0816-310 ingesting planetary fragments. Video by way of ESO/ YouTube.
Funneled as an alternative of dispersed
Earlier theories acknowledged that such metals ought to be evenly distributed on the floor of a white dwarf. In truth, when astronomers have discovered metals on different white dwarfs, these metals have been scattered over the floor. However within the case of WD 0816-310, the magnetic subject ionized the metals and guided them onto the magnetic poles. Co-author John Landstreet at Western College, Canada, mentioned:
Surprisingly, the fabric was not evenly combined over the floor of the star, as predicted by concept. As a substitute, this scar is a concentrated patch of planetary materials, held in place by the identical magnetic subject that has guided the infalling fragments. Nothing like this has been seen earlier than.
Backside line: Astronomers have found a novel metallic scar on a cannibal star, a white dwarf or “useless” star. They consider it shaped when the star consumed considered one of its planets
Source: Discovery of Magnetically Guided Metal Accretion onto a Polluted White Dwarf
Read more: Evidence for white dwarfs consuming Earth-like worlds
Read more: This white dwarf star has a giant, evaporating planet
