TESS telescope discovers two Neptune-like exoplanets

Using data collected by the TESS Space Telescope, an international team of researchers has discovered two exoplanets. They are comparable in size to Neptune.

Hot Neptune in the artist’s image. Source: NASA/JPL-Caltech

The discovery was made during the study of TOI-5126, a bright star of spectral class F. The TESS telescope could detect periodic decreases in the brightness of the star caused by the transits of its two companions. Subsequently, another CHEOPS space telescope could confirm that it really was about planetary objects.

The exoplanet located closer to the star was designated TOI-5126 b. Its radius is 4.74 Earth radii. Thus, it is about 22% larger than Neptune. The orbit of TOI-5126 passes at a distance of 0.065 AU (9.7 million km) from its star, it makes one orbit in 5.46 days. Because of this proximity, its atmosphere is warmed up to high values. The equilibrium temperature of TOI-5126 b is 1170 °C, the planet has been classified as a hot super-Neptune.

The second exoplanet, TOI-5126 c, has an orbital period of 17.9 days and is about 0.144 AU (21.5 million km) away from the parent star. Analysis of the TESS data shows that TOI-5126 c has a radius equal to 3.86 of the Earth’s radius. The equilibrium temperature of its surface is 700 °C. The exoplanet has been classified as a warm Neptune.

As for the parent star, TOI-5126, it is about 24% larger and more massive than the Sun. The luminary is located about 525 light-years from Earth, its age is 800 million years. 

Astronomers intend to continue studying this system. The data obtained during the new observations will help them better understand the difference in the composition of the atmosphere between hot and warm exo-Neptunes.

According to https://phys.org

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