Astronomers find rock types that are different from those in the Solar System.
REPUBLIKA.CO.ID, CALIFORNIA — Decades of research, astronomers have so far discovered more than 4,000 planets beyond solar system or exasuration. However, there is not yet a good consensus on what kinds of materials make up this world.
Kini, pAstronomers have made the first estimates of the rock types present on planets orbiting nearby stars. The team of astronomers discovered that this rock type is composed of exotic and diverse materials found nowhere else in the solar system.
In an effort to find this out, and find out if this world is similar to Earth, Noirlab National Science Foundation (NSF) astronomer Siyi Xu teamed up with geologist Keith Putirka of California State University, Fresno. Their findings were published in the journal Nature Communications.
“While some exoplanets that have orbited polluted white dwarfs appear similar to Earth, most have exotic rock types in our solar system,” Xu said. Newsweek, Thursday (4/11).
The duo studied the atmosphere around white dwarfs, the stellar remnants left behind when stars the same size as the sun used up their nuclear fuel. This densely collapsing stellar core is a good choice for conducting such surveys because it is composed mostly of material that was once part of the stellar core, hydrogen, and helium. However, the atmosphere around white dwarfs becomes polluted when material from rocky bodies, such as planets and asteroids, falls into them.
This means that astronomers can discover what these rocky objects are made of by studying these atmospheres and detecting materials that shouldn’t be there.
Xu and Putirka selected 23 white dwarfs located 650 light-years from the sun where elements such as calcium, silicon, magnesium and iron have previously been detected by telescopes such as the Hubble Space Telescope. They reconstructed the minerals and rocks that would store an abundance of these elements.
The white dwarfs they studied had far more varied and exotic materials than those found in the rocky bodies of the inner solar system. This suggests that the planets around the white dwarf they studied have a wider range of rock types than those found in our solar system.
In fact, some of these rock types are so exotic, the duo had to give them new names, including “quartz pyroxenites” and “periclase dunites.”
Putirka explained that some of the rock types we see from the white dwarf data will dissolve more water than rocks on Earth and may have an impact on how the oceans develop.
“Some rock types may have melted at much lower temperatures and produced a thicker crust than Earth’s rock, and some rock types may have been weaker, which may have facilitated the development of plate tectonics,” he explained.
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