NASA’s TESS Mission has Detected a Small Exoplanet Resembling Neptune in Size
By employing NASA’s Transiting Exoplanet Survey Satellite (TESS), a group of astronomers from around the world has detected a fresh, substantial, and compact exoplanet. This recently discovered extraterrestrial planet, named TOI-332 b, ranks among the most densely-packed Neptune-sized planets ever observed. The discovery is detailed in a paper released on August 23 and available on the arXiv pre-print server.
Hunting Exoplanets Among Sun’s Neighbors
In fact, TESS, NASA’s Transiting Exoplanet Survey Satellite, is currently engaged in a mission to survey approximately 200,000 of the sun’s nearest and brightest stars, with the primary objective of detecting exoplanets that transit across these stars. To date, the mission has successfully identified nearly 6,800 potential exoplanets, referred to as TESS Objects of Interest (TOI), with 379 of them confirmed.
A team of astronomers, led by Ares Osborn from the University of Warwick, UK, has now substantiated the exoplanetary status of another TOI that was monitored by TESS. They discerned a transit signal within the light curve of a K-dwarf star known as TOI-332, or TIC 139285832. The planetary nature of this signal was corroborated through subsequent ground-based observations.
In their research paper, the astronomers detailed the TESS observations of the TOI-332 system (TIC 139285832), which occurred during TESS Sectors 1 (July 25—Aug 22, 2018) and 2 (August 22—September 20, 2018). These observations involved a 30-minute cadence in the full-frame images (FFIs).
A High-Density Exoplanet with Extreme Characteristics
TOI-332 b, the newfound exoplanet, possesses a radius approximately 3.2 times that of Earth and an unusually substantial mass equivalent to 57.2 times that of Earth. This results in an exceedingly high density of approximately 9.6 grams per cubic centimeter. TOI-332 b orbits its host star every 18.65 hours at a close distance of 0.016 astronomical units (AU). The equilibrium temperature on the surface of TOI-332 b was calculated to be approximately 1,871 Kelvin.
However, based on these observations, the astronomers have classified TOI-332 b as an ultra-short period (USP) Neptune-sized exoplanet. Notably, it resides within what is known as the “Neptunian desert,” an area in parameter space characterized by the combination of radius, mass, and orbital period where such planets have been rarely observed. This desert encompasses planets with radii ranging from 2 to 9 times that of Earth, masses spanning from 10 to 250 times that of Earth, and orbital periods shorter than five days.
TOI-332 b’s Unusual Composition Challenges Established Planet Formation Theories
The researchers have also suggested that TOI-332 b’s interior composition is likely dominated by refractory materials, potentially resembling terrestrial planets more closely. However, they believe it may possess a minimal hydrogen-helium envelope, a feature that challenges existing planetary formation theories.
To conclude, turning to TOI-332’s host star, it has a spectral type of K0V and is estimated to be approximately five billion years old. Situated at a distance of about 726.5 light-years from Earth, this star is roughly 12% smaller and less massive than our sun. The effective temperature of TOI-332 was determined to be 5,251 Kelvin.
Read the original article on: Phys Org
Read more: Recent Image Unveils the Mysteries Surrounding the Formation of Planets
