Rocky planet Ross 128b looks familiar, but is not Earth’s twin
Last year, the world was electrified by the news of the discovery of the exoplanet Ross 128b, which is only 11 light years from Earth. New research has for the first time determined the chemical composition of the planet’s parent star, Ross 128.
Behind the new research is Diogo Souto of Brazil’s Observatório Nacional. The scientist and his team were able to determine what elements and in what quantity make up the star Ross 128. This knowledge makes it possible to estimate the chemical composition of planets circulating wokół stars.
– Until recently, it was difficult to get a detailedóThe report provides information on the elementsóin included in this type of star,” said Souto, whoóry has developed a new technique for taking these measurementsów last year.
The research on Ross 128 was published on „The Astrophysical Journal Lester”.
About 70 percent of all stars in the Milky Way, including Ross 128, are red dwarfs, whichóre are much cooler and smaller than our Sun. Based on the results of a major surveyóin the sky, in whichóhe search for extrasolar planets, astronomers estimate that many of these red dwarfsów has at least one exoplanet.
Several systemóin planetary wokół of this type of star has dominated in recent years with the suddenówki serviceóin informational. We are talking, for example, about Proxima b, a planet orbiting the closest star to us outside the Sun – Proxime Centauri or the seven planets orbiting wokół TRAPPIST-1, whichóra is not much larger than Jupiter.
Teamół scientistsów under the direction of Souto, using the APOGEE spectroscope, performed a near-infrared spectrum analysis of the Ross 128 star to determine the amounts of carbon, oxygen, magnesium, aluminum, calcium, potassium, titanium and iron in the star.
– APOGEE’s ability to measure near-infrared light, in which theórym Ross 128 is the brightest, was key to this study. This has allowed us to answer fundamental questions about Ross 128b’s similarity to Earth – said Joanna Teske of the Carnegie Institution for Science, wspóauthor of the publication.
When stars are young, they are surrounded by a disk of rotating gas and dust, with którego form rocky planets over time. The chemistry of a star can affect the contents of the disk, as well as the resulting mineralogy and structure of the planet’s interior. For example, the amount of magnesium, iron and silicon in a planet will control the ratio of the masses of its inner layers of nucleus and mantle.
Syndromeół determined that Ross 128 has iron levels similar to our Sun. Although the researchers were unable to measure the amount of silicon, the ratio of iron to magnesium in the star indicates that the nucleus of the planet Ross 128b, should be larger than the nucleus of Earth. Scientists knew the minimum mass of Ross 128b, and through the study they learned the chemical composition of the star, this allowed them to estimate the radius range of the planet, whichóre not directly measurable due to the way itób, in which the planet’s orbit is oriented around theół stars relative to our planet.
Knowing a planet’s mass and radius is important for understanding what it is made of, since these two measurements can be used to calculate its density. Researchers have concluded that planets with a radius greater than about 1.7 Earth radii are likely shielded by a gaseous envelope, much like Neptune in our solar system. In contrast, those with smaller radii are likely to be more rocky, like our planet.
The estimated radius of exoplanet Ross 128b indicates that it is a rocky planet. By measuring the planet’s temperature and relying on previous calculations, the researchers were also able to determine the amount of light która reaches the planet. It turned out that our neighbor has a moderate climate.
– It’s amazing what we can learn about another planet by analyzing what the radiation of the parent star mówi us about the chemistry of the entire planetary system. Although Ross 128b is not Earth’s twin, and we still know little about its potential geologic activity, we have been able to strengthen the argument that it is a temperate planet, whichóThe surface could potentially hold liquid water – admitted Souto.