![new white dwarf magazine new white dwarf magazine](https://images-na.ssl-images-amazon.com/images/I/916TOzHQuOL.jpg)
"Some rock types might melt at much lower temperatures and produce thicker crust than Earth rocks, and some rock types might be weaker, which might facilitate the development of plate tectonics."Įarlier studies of polluted white dwarfs had found elements from rocky bodies, including calcium, aluminum, and lithium. "Some of the rock types that we see from the white dwarf data would dissolve more water than rocks on Earth and might impact how oceans are developed," he explained.
![new white dwarf magazine new white dwarf magazine](https://www.newsstand.co.uk/issueimages/535x745/2680057.jpg)
Putirka describes what these new rock types might mean for the rocky worlds they belong to. "They have no direct counterparts in the Solar System." "While some exoplanets that once orbited polluted white dwarfs appear similar to Earth, most have rock types that are exotic to our Solar System," said Xu. In fact, some of the compositions are so unusual that Putirka and Xu had to create new names (such as "quartz pyroxenites" and "periclase dunites") to classify the novel rock types that must have existed on those planets. They found that these white dwarfs have a much wider range of compositions than any of the inner planets in our Solar System, suggesting their planets had a wider variety of rock types.
![new white dwarf magazine new white dwarf magazine](https://52f4e29a8321344e30ae-0f55c9129972ac85d6b1f4e703468e6b.ssl.cf2.rackcdn.com/products/pictures/204304.jpg)
The scientists then used the measured abundances of those elements to reconstruct the minerals and rocks that would form from them. Keck Observatory in Hawai'i, the Hubble Space Telescope, and other observatories. Putirka and Xu looked at 23 polluted white dwarfs, all within about 650 light-years of the Sun, where calcium, silicon, magnesium, and iron had been measured with precision using the W. By looking for elements that wouldn't naturally exist in a white dwarf's atmosphere (anything other than hydrogen and helium), scientists can figure out what the rocky planetary objects that fell into the star were made of. These are the dense, collapsed cores of once-normal stars like the Sun that contain foreign material from planets, asteroids, or other rocky bodies that once orbited the star but eventually fell into the white dwarf and "contaminated" its atmosphere. To try to find out, astronomer Siyi Xu of NSF's NOIRLab partnered with geologist Keith Putirka of California State University, Fresno, to study the atmospheres of what are known as polluted white dwarfs. However, it's difficult to know what exactly these planets are made of, or whether any resemble Earth. Astronomers have discovered thousands of planets orbiting stars in our galaxy - known as exoplanets.