Inspenet, December 4, 2023.
A team of scientists has discovered a solar system of 6 planets orbiting the star HD110067 in a synchronized dance, a phenomenon known as orbital resonance.
This type of feature is rare in systems, indicating that it has not experienced significant changes throughout its billion-year history. Researchers consider this discovery to be fundamental for a better understanding of planetary formation processes.
Located approximately 100 light years away in the constellation of Coma Berenices is HD110067, a star that is 20% smaller and cooler than the Sun. The first signs of the presence of a planetary system around this star emerged in 2020.
Solar system of 6 planets: How was its discovery?
NASA’s TESS planet-hunting telescope detected a decrease in the star’s brightness, similar to an eclipse, suggesting the presence of at least two planets transiting in front of it. Two years later, new TESS observations presented data that contradicted the initial interpretation. This disagreement caught the attention of Spanish astrophysicist Rafael Luque of the University of Chicago and his colleagues. “At that point, we decided to use CHEOPS. We analyze signals in all possible periods that these planets could have“Luque narrated.
Using ESA’s CHEOPS space telescope, they managed to identify a third exoplanet. This finding turned out to be the key to unraveling the entire system, as the three planets were confirmed to be in orbital resonance. The astrophysicist states that “CHEOPS provided us with a configuration that allowed us to anticipate the others.” Through what they describe as a “detective-esque” approach, combining data from both telescopes and using mathematical models of gravitational interactions, they were able to predict the existence of three additional planets in the system.
Later observations confirmed that the planets were located exactly where this resonance pattern predicted, forming a chain that follows the 3:2 rhythm. The outermost planet has an orbital period of 20,519 days, almost 1.5 times the period of the next planet, which is 13,673 days. The latter, in turn, has a period approximately 1.5 times longer than that of the inner planet, with 9,114 days.
In other words, when the planet closest to the star completes three orbits, the second planet completes exactly two during the same period. This arrangement is known as 3:2 resonance. The six planets make up a resonant chain with pairs of 3:2, 3:2, 3:2, 4:3 and 4:3, according to the ESA explanation. This means that the nearest planet makes six orbits in the same time that the outermost planet makes one. Researchers do not rule out the possibility that there are more coordinated planets in this system .
The exoplanets hosted on HD110067 are classified as sub-Neptunes, meaning they are smaller than Neptune and have a diameter four times that of Earth. Regarding their characterization, Ignasi Ribas, CSIC astrophysicist and collaborator in the research, points out that they do not resemble the Earth, since they have very high temperatures that can reach 200 degrees.
HD110067 stands out as the most luminous system yet identified that hosts four or more planets. These worlds presumably have atmospheres with a significant presence of hydrogen, making them favorable candidates for future analyzes aimed at discerning their chemical composition and other atmospheric properties.
Planets discovered outside the solar system
Although only one planetary group called the “solar system” is officially recognized, scientific research has identified stars with planets in orbit around them.
To date, science has identified 5,000 exoplanets, which are planets outside our solar system, in a variety of planetary systems in the Milky Way. These detections have been possible thanks to technological advances and space missions specialized in the search and characterization of these worlds beyond our own galaxy.
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