The Transiting Exoplanet Survey Satellite (TESS) of NASA has made a thrilling discovery, disclosing a new exoplanet known as TOI-2498 b that is hot and bloated. This celestial object, classified as a “super-Neptune,” is six times larger and thirty-five times more massive than the Earth.
The Transiting Exoplanet Survey Satellite (TESS) seeks to identify transiting exoplanets orbiting the sun’s nearest luminous stars. To date, TESS has identified approximately 6,600 potential exoplanets and 331 confirmed ones.
26 Times the Size of the Sun
During its primary mission, TESS observed TOI-2498 (also known as TIC-263179590), a G-type solar-type star that is 26% larger and 12% more massive than the sun.
TESS monitoring data from 12 December 2018 to 6 January 2019 revealed a transit signal in the light curve of the star. Further research, including spectroscopic and photometric observations conducted by Ginger Frame of the University of Warwick in the United Kingdom, confirmed the signal’s planetary origin.
The team of Dr. Frame utilized photometry from TESS sectors 6 and 33, in addition to ground-based photometry from LCOGT and spectroscopy from HARPS. Their research revealed the discovery of a super-Neptune that orbits a G-type star and is extremely heated and distended.
The newly discovered exoplanet has an estimated radius of 6.06 times that of Earth and a mass of 34.62 times that of Earth. It has a relatively low density, measuring 0.86 g/cm3.
Every 3.74 days, TOI-2498 b completes an orbit around its host star at a distance of roughly 0.05 AU. The team’s calculations imply an equilibrium temperature of approximately 1,443 K.
Frame’s team classifies TOI-2498 b as a heated and obese super-Neptune based on their findings. The planet’s low density indicates the presence of a 27 percent nebulous envelope.
However, the researchers observe that their planetary model assumes that TOI-2498 b has no substantial water content or atmospheric metallicity.
Between Saturn and Neptune
In a summary of their research, the scientists emphasize the stability of TOI-2498 b as a super-Neptune, indicating minimal evaporation relative to its mass over the planet’s lifetime.
They hypothesize that the planet initially formed as a large, Saturn-sized world with an envelope mass fraction of between 30 and 45 percent, before shrinking steadily over approximately 3.6 billion years.
The research team believes TOI-2498 b was originally a planet resembling Saturn before it shrunk to its present size. This discovery expands our knowledge of the universe beyond the solar system by shedding light on the intriguing diversity and evolution of exoplanets.
The team’s findings were published in the Royal Astronomical Society’s Monthly Notices.
In related news, TESS discovered a new “super-Earth” exoplanet with an unusually low density. This item is TOI-244, also known as GJ 1018. It is an M2.5 V early-type M-dwarf star that is nearby and bright. This indicates that this exoplanet is approximately half the size and mass of the sun.