Astronomers have recently announced the discovery of a new Saturn-sized exoplanet orbiting a young solar-type star. The planet, named TOI-1135 b, is one of the few examples of giant planets detected by the astrometric technique, which measures the tiny wobble of the star caused by the gravitational pull of the planet. The planet was also observed by NASA’s Transiting Exoplanet Survey Satellite (TESS), which confirmed its size and orbital period.
The Astrometric Technique
The astrometric technique is a method of finding exoplanets by tracking the precise position of a star in the sky and detecting any small deviations from its expected motion. These deviations are caused by the presence of a planet that orbits the star and makes it wobble around the center of mass of the system. The larger the planet and the farther it is from the star, the larger the wobble. This technique is especially useful for finding Jupiter-like planets in wide orbits, which are difficult to detect by other methods such as transit or radial velocity.
The Discovery of TOI-1135 b
TOI-1135 b was discovered by an international team of astronomers led by Manuel Mallorquín Díaz of the University of La Laguna, Spain. They used data from TESS and from the Very Long Baseline Array (VLBA), a network of radio telescopes across North America. They identified a transit signal in the light curve of TOI-1135, a young solar-type star of spectral type G0 located about 371 light-years away from Earth. They also measured the astrometric wobble of the star using VLBA observations spanning over a decade. By combining these two datasets, they were able to determine the mass, radius, density and orbital parameters of the planet.
The Properties of TOI-1135 b
TOI-1135 b has a radius of about 0.8 Jupiter radii and a mass of about 0.062 Jupiter masses, which gives it a density of about 0.16 g/cm3. The planet orbits its host star every 8.02 days at a distance of about 0.082 AU, which is closer than Mercury is to the Sun. The equilibrium temperature of TOI-1135 b is estimated to be between 950 and 1200 K, which makes it a hot and inflated exoplanet. The planet has an extended atmosphere that is likely losing mass due to the intense stellar radiation. The astronomers estimate that TOI-1135 b has a high mass-loss rate of about 39 Earth masses per billion years, which means that it will eventually lose most of its atmosphere in a few hundred million years.
The Significance of TOI-1135 b
TOI-1135 b is one of the few examples of giant planets detected by both transit and astrometry, which allows for a more accurate characterization of its properties. It is also one of the few Saturn-sized exoplanets known to orbit young solar-type stars, which provides insights into the formation and evolution of such planets. Moreover, TOI-1135 b is an interesting target for atmospheric studies, as it may show signs of atmospheric escape and photoevaporation.
Conclusion
The discovery of TOI-1135 b demonstrates the power and potential of combining different techniques and instruments to find and characterize exoplanets. It also adds to our knowledge and diversity of Saturn-sized exoplanets, which are still poorly understood compared to other types of planets. TOI-1135 b is a new astronomical discovery that will inspire further research and exploration.
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