(ORDO NEWS) — Using NASA‘s Transiting Exoplanet Survey Satellite (TESS), astronomers from Pennsylvania State University, USA, and other scientific organizations have discovered an extrasolar planet the size of Jupiter.
This newly discovered exoplanet, designated TOI-3757 b, is slightly larger than Jupiter, but its mass is almost three times less than that of the largest planet in the solar system.
The TESS mission is surveying some 200,000 of the brightest stars around the sun to look for transiting exoplanets. In their work, a team of astronomers led by Shubham Kanodia of the University of Pennsylvania confirmed a new candidate planet discovered using the TESS satellite.
In the paper, the team reports the identification of a transit signal in the light curve of TOI-3757, an M-type dwarf star. The signal’s planetary nature was confirmed by additional observations.
Planet TOI-3757 b has a radius on the order of 1.09 Jupiter radii, while its mass is roughly equivalent to 0.268 Jupiter masses. This gives a density value of 0.27 grams per cubic centimeter, which is the lowest density of matter among the planets orbiting M dwarfs known to science at present.
The exoplanet revolves around the parent star with a period of 3.44 days, being at a distance of 0.038 astronomical units (1 AU is equal to the average distance from the Earth to the Sun) from the star. The equilibrium temperature for this exoplanet is about 759 Kelvin.
Located about 578 light-years from Earth, TOI-3757’s parent star is an M0V dwarf, about 37 percent smaller in mass and size than the Sun.
The star has a metallicity close to that of the sun; its age is about 7.1 billion years, and the effective temperature is at the level of 3913 Kelvin. The paper notes that the star TOI-3757 has the lowest metallicity among all M-type dwarfs in whose systems gas giants are known.
In an attempt to explain the low density of the planet TOI-3757 b, the authors propose two possible hypotheses. According to the first version, the low metallicity of the parent star may be responsible for the late onset of the avalanche-like accretion of gas in the period before the dissipation of the protoplanetary disk.
The second hypothesis suggests that the formation of the planet is the result of evolutionary mechanisms in which tidal heating, due to a small orbital eccentricity, causes inflation of the planet.
The researchers added that the second scenario could be confirmed by measurements of methane and ammonia. Such a study would help put limits on the internal temperature of the star TOI-3757, and this, in turn, would help to estimate the degree of heating due to tidal forces, they added.
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