Exotic extrasolar planets rich in sapphires and rubies
Astronomers have discovered extrasolar planets so exotic that they have proposed an entirely new class for them. These worlds were formed at high temperatures close to their parent stars and contain large amounts of calcium, aluminum and their oxides – including sapphire and ruby.
One such planet is located in the constellation Cassiopeia at a distance of 21 light years from us. HD219134b orbits its star in just three days and has a mass almost five times that of the Earth, making it one of the so-called super-Earths.
A new class of planets tends to orbit wokoł their stars much closer than Earth or most of the exoplanets that have been discovered. This means that if they circulate aroundoł places whereorym they formed, their composition can be very ro¿ny. Instead of an iron core like Earth’s, they are rich in calcium and clay. This, in turn, could mean the presence of rubiesoin and sapphiresow.
Research by scientistsow of the universityoin Zurich, Switzerland, and Cambridge, UK, were published in the „Monthly Notices of Royal Astronomical Society”.
Astronomers have so far identified three such planets. This is the aforementioned HD 219134b, 55 Cancri e, ktora is located 41 light years from our solar system and orbits its star in just 18 hours, and WASP-47 e, located at a distance of 870 light years from us. WASP-47 e orbit their parent star similarly to 55 Cancri e – within 18 hours.
– Perhaps HD 219134b shimmers red and blue, like rubies and sapphires, because these gemstones are aluminum oxides common on this exoplanet, said Caroline Dorn, an astrophysicist at the University of Zurich.
Scientists are studying the formation of planets using theoretical models and porocompare their results with observational data. It is known that during their formation, stars like the Sun were surrounded by a disk of gas and dust, in which theorym planets were born. Rocky planets such as Earth formed from the remnants of solid bodies when the protoplanetary gas disk dissipated and its remaining elements cooled down. Planets formed in this way have an Earth-like composition with an iron core. Most of the known superziem were formed in such regions.
But there are also regions close to the star where it is much warmer. – There many elementsow is still in the gas phase, and the planets‘ elements have a completely different position – stated Dorn. In their models, the teamoł research team has calculated what a planet formed in such a hot region should look like. According to the calculations, calcium and aluminum are the mainownymi components besides magnesium and silicon, and iron is almost absent.
– For this reason, such planets cannot, for example, have a magnetic field like the Earth has,” admitted Dorn. And because the internal structure is so rothat are farther from our planet, their atmospheres will rodiffer from normal superziem. Therefore, the teamoł scientistsoin mowi about a new, exotic class of planets formed from condensateow of high temperature.
– The exciting thing about these objects is that they are completely rodifferent from most Earth-like planets. In our calculations, we found that these planets have 10 to 20 percent lower density than Earth’s – explained Dorn.
These calculations led researchers to analyze other exoplanets with similarly low density. For example, a thick atmosphere can lead to a lower ogol of low density. But two of the exoplanets studied, 55 Cancri e and WASP-47 e, orbit their star so closely that their surface temperature is nearly 3,000 degrees. Under such conditions, they would have long ago lost their gaseous envelope.
Although it is not so hot on HD219134b, the situation seems more complicated. At first glance, the lower density can be explained by deep oceans of magma, although researchers have not been able to assess whether such oceans of magma can contribute to the lower density.
– We found three candidates, whichore may belong to a new class of super-Earths of exotic composition,” concludes the astrophysicist. By the way, the astronomers corrected earlier reports of 55 Cancri e, whichory movividly about „diamonds falling from the sky”. Researchers had previously assumed that the planet was composed of mainlyotially made of carbon, but they had to abandon this theory on the basis of subsequent observations. – We transformed the alleged diamond planet into a sapphire planet, Dorn joked.
Sourceobackground: University of Zurich, fot. Thibaut Roger/ University of Zurich