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Distant rocky planets may be very different from Earth

U.S.A.Distant rocky planets may be very different from Earth

Rocky exoplanets may be very different from our neighbors in the Solar System (NASA)

Astronomers have discovered more than 4100 planets orbiting stars in our galaxy, which is known as exoplanets, One of the many questions that experts ask is how they are composed or If any resemble the earth, with the possible idea that they harbor life.

To try to find out, Sia Xu, an astronomer at the National Research Laboratory working in Optical-Infrared Astronomy at the National Science Foundation of the United States with geologist Keith Putirka of California State University, Studied the atmospheres known as polluted white dwarf stars. These distant bright objects are the dense, collapsed cores of once normal stars like our Sun., and containing material that was once planets, asteroids, or other rocky bodies. Objects that orbited the star in the distant past, but which at some point fell on this white dwarf and “polluted” its atmosphere.

TOI 700 d exoplanet is a distant world that could host life (Twitter NASA Exoplanets / @NASAExoplanets)
TOI 700 d exoplanet is a distant world that could host life (Twitter NASA Exoplanets / @NASAExoplanets)

Experts Look for Elements That Wouldn’t Exist Naturally in a White Dwarf’s Environment (i.e. anything other than hydrogen and helium), to identify what the rocky planetary bodies that fell on the star were made of. Putirka and Xu observed 23 corrupt white dwarfs located at a distance of about 650 light years from the Sun, In which elements such as calcium, silicon, magnesium and iron were precisely detected, thanks to observations made at the W.M. Keck Observatory in Hawaii, the Hubble Space Telescope and other observatories.

,What We’re Used To Thinking, These Planets Might Be Totally Alien“Scientific work published in the journal, explained Putirka, a geologist at California State University in Fresno” nature communication, But Caltech planetary scientist David Stevenson warns that finding out that a missing planet is made up of what’s left behind is fraught with difficulties. ,Rocky worlds outside the Solar System may have exotic chemical composition”, slipped. Scientists used abundant measurements of these elements to reconstruct the minerals and rocks that formed from them.

They found that these white dwarfs have a wider range of compositions than any inner planet in our solar system, suggesting that their planets contained a wider variety of rock types., In fact, some of the compositions are so unusual that researchers had to come up with new names (such as “quartz pyroxenites” and “periclase dunites”) to classify the new types of rocks that once existed on those planets. “While some exoplanets that have orbited corrupt white dwarfs in the past appear similar to Earth, most have rock types that are alien to our solar system. They have no direct counterparts,” Xu said.

The image shows a comparison between the exoplanet system of the star L 98-59 (above) with a portion of the inner Solar System (Mercury, Venus and Earth), and highlights the similarities that exist between the two systems.  Image provided by European Southern Observatory (ESO).  (EFE).
The image shows a comparison between the exoplanet system of the star L 98-59 (above) with a portion of the inner Solar System (Mercury, Venus and Earth), and highlights the similarities that exist between the two systems. Image provided by European Southern Observatory (ESO). (EFE).

After a Sun-like star expands into a red giant, it eventually ejects its atmosphere, leaving behind its smaller, denser core, which becomes a white dwarf. That star’s great gravity pulls heavy chemical elements into its interior, which is why most white dwarfs have pristine surfaces of hydrogen and helium.

But more than a quarter of these stars are playing surfaces with heavier elements like silicon and iron, possibly from planets that once orbited the star and met its ends when it expanded into a red giant. The heavy elements of these white dwarfs have not yet had time to sink beneath the stellar surface.

Putirka described some of the characteristics of this new type of rock that formed distant rocky bodies at some point: “Some types of rocks that we see from white dwarf data dissolve in more water than rocks on Earth and can affect the way oceans develop. Some types of rock can melt at very low temperatures and produce a crust thicker than rocks on Earth, and some types of rock can be weakened, which may facilitate the development of plate tectonics.” They said.

By isolating a preliminary list of volatiles in a model of the geochemical evolution of rocky planets, they derived several scenarios in which a lifeless rocky planet around a Sun-like star might have evolved to acquire oxygen (J. )
By isolating a preliminary list of volatiles in a model of the geochemical evolution of rocky planets, they derived several scenarios in which a lifeless rocky planet around a Sun-like star might have evolved to acquire oxygen (J. )

Elements of rocky bodies such as calcium, aluminum and lithium were found in previous studies of contaminated white dwarfs. Even then, Putirka and Xu show that these are minor elements (which usually make up a small part of terrestrial rock) and the measurement of the major elements (which make up a large proportion of a terrestrial rock), especially silicon, are needed to know exactly what types of rock may have been present on those planets. Furthermore, Putirka and Xu claim that the high levels of magnesium and low levels of silicon measured in the atmospheres of white dwarfs suggest that the rocky debris likely came from inside the planets, not their crust.

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Some previous studies of contaminated white dwarfs had speculated that continental crust existed on rocky planets that once orbited those stars, but Xu and Putirka found no evidence of crust rocks., However, observations do not completely rule out that the planets had continental crust or other types of crust. “We believe that there is rock in Earth’s crust, we cannot see it, probably because it occurs in a much smaller fraction than the mass of other planetary components, such as the core and mantle,” Putirka said. ,

By examining white dwarfs 650 light-years away from the Sun, Putirka and Xu came to a surprising conclusion about broken rocky planets. Contrary to conventional wisdom, most of their planetary systems did not resemble the Sun’s rocky planets.: Mercury, Venus, Earth and Mars, the researchers say.

Proxima Centauri, the closest star to the Sun and home to a rocky planet at the optimum distance for liquid water, has emitted at least 23 large flares over the past two years (NASA, ESA, and G. BACON - STSCI)
Proxima Centauri, the closest star to the Sun and home to a rocky planet at the optimum distance for liquid water, has emitted at least 23 large flares over the past two years (NASA, ESA, and G. BACON – STSCI)

“For example, some white dwarfs contain a lot of silicon. This suggests that their planetary mantles contain quartz, a mineral that in its purest form is composed entirely of silicon and oxygen. But Earth There is very little, if any, quartz in the mantle. A planet with a quartz-rich mantle is probably very different from Earth.Putirka pointed. Such exotic mineral compositions can affect, for example, volcanic eruptions, continental drift, and the fraction of a planet’s surface that consists of oceans versus continents. And all these phenomena can affect the development of life.

The rocky worlds around sun-like stars are difficult to destroy, says Stevenson. The destruction of the planets is first done by the bright light of the red giant. They can then be engulfed by the expanding atmosphere of the star and crash into another planet. Each of these traumatic events could change the fundamental makeup of a planet, as well as possibly send some elements toward white dwarfs before others., As a result, planetary debris that ends up on the surface of the star in a snapshot in time may not reflect the initial makeup of the world.

Xu agrees that astronomers don’t know exactly how the breakdown develops or what elements fall on the white dwarf. Future theoretical studies may provide information on the matter. He also noted that astronomers have found that asteroids scatter around white dwarfs, offering a small window into the actual break-up process. And future observations of these white dwarfs, they say, could help reveal any changes in elemental composition over time.

According to Xu, the combination of an astronomer and a geologist was key to uncovering the secrets hidden in the atmosphere of corrupted white dwarfs. “I met Keith Putirka at a conference and was excited that he could help me understand the systems that I was seeing. He taught me geology and I taught him astronomy, and we figured out what these mysterious exoplanets are. How to understand the system.”

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