Astrônomos have identified an unusual planetary system around the star TOI-201. NASA’s TESS probe detected the signals along with ground-based observations made on Planalto Antártico. The set brings together three very different bodies that interact dynamically.
The study published this week confirms details that differentiate the system from others already known. The star is about 370 light-years from Terra, in the constellation Pictor. Ela is type F, with a mass and diameter about 1.3 times those of Sol and an estimated age of around 870 million years.
Super-Rocky Earth completes orbit in less than six days
The innermost planet, designated TOI-201 d, is classified as super-Terra. Ele has a radius of approximately 1.39 times that of Earth and a mass of around 5.8 times that of Earth. The orbital period is 5.85 Earth days.
The calculated density comes to about 11 grams per cubic centimeter. Isso indicates rock composition with possible dense core. The orbit has a moderate eccentricity of 0.3. The planet is too close to the star, making it too hot for liquid water on the surface.
Hot gaseous Gigante orbits every 53 days
TOI-201 b is a gas giant with a mass equivalent to about half that of Júpiter. The orbital period measures 53 days. Esse world type is given the classification of hot or warm Júpiter, as it orbits further away than the very hot Júpiteres, but still within relatively short distances.
The planet has an orbit with moderate eccentricity. Astrônomos monitored variations in the timing of transits to understand disturbances caused by other bodies. Dados radial velocity helped refine the mass with an accuracy of 0.52 plus or minus 0.02 masses of Júpiter.
- TOI-201 d: rocky super-Terra, period 5.85 days, mass about 5.8 times that of Earth
- TOI-201 b: gas giant, period of 53 days, mass about 0.52 times that of Júpiter
- TOI-201 c: massive companion with a period of about 2,890 days, mass approximately 15.7 times that of Júpiter
External Companheiro with long, elliptical orbit influences entire system
The third component, TOI-201 c, has an orbital period of approximately 2,890 days, or almost eight Earth years. Sua’s mass reaches 15.7 times that of Júpiter, a value that places it in the range of brown dwarfs, just above the deuterium burning limit. The orbit is highly eccentric, with a value of 0.65.
Essa’s elongated configuration makes the object approach the star at distances smaller than Marte’s orbit in some points and move further away from Júpiter’s in others. The partial transit detected in TESS data allowed us to confirm its presence. The next line-of-sight pass is expected to occur in March 2031.
Different Inclinações generate observable changes in internal orbits
Planets do not share the same orbital plane. Essa lack of coplanarity, combined with the masses and distances, causes strong gravitational interactions. The outer companion exerts force on the inner worlds, which changes the orientation of their orbits over time.
Astrônomos estimate that the current configuration of visible transits should last around 200 years. Depois In addition, the inner planets will no longer cross the face of the star from Earth’s perspective for thousands of years. Simulações dynamics point to von Zeipel-Kozai-Lidov type oscillations as the main mechanism.
Telescópio ASTEP on Antártida contributed to accurate measurements
The ASTEP project, installed on Estação Concordia, recorded transits supported by the long polar nights. The observatory sits on a 3.2-kilometer-deep glacier and enjoys stable visibility conditions. Parcerias involved teams from Universidade from Birmingham, Observatoire from Côte d’Azur and other institutions.
Complementary Dados came from the LCOGT network in different hemispheres and from spectrographs such as CORALIE, HARPS and PFS. The combination of transit photometry, transit time variations, radial velocities and astrometry made it possible to map the system in three dimensions. Ismael Mireles, of Universidade of Novo México, led the work.
The article appeared in Science Advances magazine on April 15. The discovery reinforces that planetary systems can present very varied architectures soon after formation. No Sistema Solar, the planets are almost all coplanar, but here each body follows different parameters.
Astrônomos continues to monitor the system to refine parameters. The next transit of the external object will provide additional observation opportunity. Estudos like this help test models of formation and evolution of multiple systems.
