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EI2GYB > ASTRO 30.10.25 15:02z 44 Lines 4283 Bytes #128 (0) @ WW
BID : 47074_EI2GYB
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Subj: Mini-Neptune exoplanet orbiting bright K-type star discover
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Mini-Neptune exoplanet orbiting bright K-type star discovered with TESS
Using NASA's Transiting Exoplanet Survey Satellite (TESS), an international team of astronomers have detected a new exoplanet orbiting a bright K-type star known as TOI-283. The newfound alien world, which received the designation TOI-283 b, is about 40% smaller than Neptune. The discovery was detailed in a research paper published October 16 on the pre-print server arXiv.
TESS is searching for extrasolar worlds transiting bright and nearby stars. To date, it has identified more than 7,700 candidate exoplanets (TESS Objects of Interest, or TOI), and 705 of them have been confirmed by follow-up observations.
Located some 269 light years away, TIC 382626661 is a bright K-type star about 15% smaller and 20% less massive than the sun. The star has been observed with TESS since 2018, which resulted in the detection of a transit signal in its light curve and it received the designation TOI-283.
A group of astronomers led by Felipe Murgas of the University of La Laguna, Spain, carried out follow-up photometric and spectroscopic observations of TOI-283 using ground-based facilities, including the Very Large Telescope's (VLT) Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO). The observational campaign confirmed the planetary nature of the previously identified signal.
"The planet candidate was first detected by NASA's TESS mission; ground-based observations confirmed that the star has no detectable stellar companions and that the transits occur on the star TOI-283. High-precision RV [radial velocity] measurements made with the VLT's ESPRESSO instrument enabled the mass of the planet candidate to be determined," the scientists explain.
Results of the observations indicate that TOI-283 b has a radius of about 2.34 Earth radii and is approximately 6.54 times more massive than Earth, which yields a density at a level of 2.81 g/cm3. The planet orbits its host every 17.62 days, at a distance of some 0.12 AU from it. The planet's equilibrium temperature was calculated to be 661 K.
Therefore, based on the physical properties, TOI-283 b was classified as a mini-Neptune. The authors of the paper noted that the position of TOI-283 b in the mass-radius diagram and theoretical compositional models indicate that this planet has a significant contribution from light elements and is consistent with an extended hydrogen/helium-rich atmosphere and/or significant water content.
Further observations of this planet with the James Webb Space Telescope (JWST) are suggested to confirm the presence of water in its atmosphere.
When it comes to the parent star TOI-283, the collected data indicate that it has an effective temperature of 5,213 K and an iron abundance at a level of -0.09 dex. The age of the star is estimated to be 10.4 billion years.
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