Astronomers have determined that one of the stars 35 light-years from us orbits several rocky, solid-surface planets, and one of them may even be life-threatening.
This is a red dwarf star named L 98-59, around which at least four planets move; The system is very thrilling. New observations indicate exactly what previous studies suggested – the existence of a rocky planet half the mass of Venus.
New observations have also revealed other planets in this system, including the oceanic planet and the probable super-Earth, which must be in the middle of the star’s vital zone.
“A planet in a vital zone may have an atmosphere that can protect and support life,” said Maria Rosa Sapater Osorio, an astrophysicist at the Spanish Center for Astrobiology.
The discovery is quite a turning point not only in the search for planets potentially suitable for life, but also in the search directly for rocky planets similar to Earth, Mars and Venus, as the discovery of a planet half the size of Venus is already a major breakthrough.
It is the least massive exoplanet ever measured by determining its gravitational effects at its parent star position.
Although there must be more exoplanets in Deer Leap than there are stars, we have so far only proven about four thousand planets.
Because they are much smaller and paler than the stars. Consequently, the best methods available to us work best to discover more massive, planets close to our own star.
Most exoplanets are detected by the transit method. Telescopes such as Kepler (already completed the mission) and TESS observe a specific section of the sky and look for repetitive, regular eclipses in starlight caused by a planet moving around this star as it passes between us.
On the other hand, the radial velocity method looks for changes in the location of the star. Because the planets have the slightest gravitational influence on their own star, they move very little around a common orbit (so does our sun). The more massive the exoplanet, the stronger such a signal.
System L 98-59 In 2019, NASA, a space telescope hunting for planets, was discovered by the transit method; The star was orbited by three planets. With this method it is possible to get some information about the exoplanets themselves, for example, to find out their approximate size depending on how much it blocks the light of its star.
The radial velocity method can add more information. Based on how much the star is moving, astronomers can calculate the mass of the exoplanet. Once the planet is determined by size and mass, it is now possible to calculate its density, which in turn gives it a chance to determine its composition: denser exoplanets are largely rocky, light, and inflated, gaseous.
“If we want to know what the planet is made of, the minimum we need is its mass and radius,” explains Oliver Demanjon, an astronomer at the University of Porto in Portugal.
A team of astronomers led by Demanjon used the European Southern Observatory (ESO) Very Large Telescope (VLT) to conduct radial velocity measurements for the L 98-59 system. As a result, it was confirmed that the planet L 98-59b, which is the deepest in the system, has half the mass of Venus and is probably rocky.
From the inside, the second planet is 1.4 times larger than Earth and is likely to be rocky as well.
The third exoplanet is 1.5 times larger than Earth, has twice its mass, and as its density profile indicates, it must have a very high water content. Researchers estimate that more than 30 percent of the mass of this exoplanet must be water, or it may be covered by water.
To the researchers’ surprise, radial velocity measurements recorded two periodic signals that did not belong to any of the exoplanets known to them. This indicates that there are two exoplanets hidden in the system, the orbits of which do not coincide with the planes of others and do not perform transit.
The mass of the first is about three times that of the Earth, and it orbits the star once every 12.8 days. The second planet is more interesting.
“We have clues about the existence of a rocky exoplanet in the vital zone of this system,” Demanjon said.
If confirmed, the fifth planet is estimated to have 2.46 times the mass of Earth, and one orbit around the star will take up to 23 days. Such a distance may seem very close to you, but do not forget that red dwarfs are much colder stars than the sun, and therefore a moderate distance from the star, where it is not so hot or cold that the existence of a known form of life is impossible.
Unfortunately, only transit can determine whether this exoplanet has an atmosphere; Consequently, he is no longer a good candidate for further studies of life-friendly planets.
However, this finding suggests that planetary systems may have hidden too much in “wristbands” and that more observations are needed to study inner exoplanets.
“This system informs us in advance about the coming. “We, as a society, are hunting for rocky planets because, from the birth of astronomy to the present day, we are getting closer to finding a rocky planet in a vital area that may have an atmosphere,” said Oliver Demanjon, an astronomer at the University of Porto.