NASA astronomers have discovered a new inflated, low density "hot Jupiter" exoplanet using the Transiting Exoplanet Survey Satellite (TESS) full-frame images. Dubbed as the TIC 257060897b, the exoplanet is said to be 50 percent larger and 30 percent less massive than Jupiter.

TESS has been monitoring and surveying about 200,000 stars for temporary drops in brightness due to transiting exoplanets. It has already identified more than 4,500 candidate exoplanets called TESS Objects of Interest (TOI), wherein 156 have been confirmed so far.

 NASA Discovered New Inflated, Low-Density
(Photo : Wikimedia Commons)
Artist’s impression of a hot Jupiter exoplanet in the star cluster Messier 67

New Inflated Hot Jupiter Exoplanet

Astronomers reported in their paper, titled "TIC~257060897b: An Inflated, Low-Density, Hot-Jupiter Transiting a Rapidly Evolving Subgiant Star" published on October 1 in, that they have discovered a transiting exoplanet orbiting the star TIC 257060897 using TESS full frame images.

According to, TIC 257060897b has a radius of about 1.49 Jupiter radii and weighs approximately 0.67 Jupiter masses, yielding a density of 0.25 g/cm3 and revolving around its star approximately every 3.66 days at a distance of 0.05 AU. The planet has a temperature of 2,711.93 °F (1,488.85°C).

Based on the evaluation, astronomers inferred that planet TIC 257060897b is a "hot Jupiter." It has the same characteristics as the largest planet in the solar system, with orbital periods of less than 10 days. It has high surface temperatures because it orbits its parent stars closely.

But what makes this new hot Jupiter is that it is an inflated exoplanet and has the smallest densities NASA has ever recorded, unlike other giant planets that expand when their parent stars are nearing their death.

Astronomers have long known about inflated planets, but it remains a mystery as to what causes the inflation process. Scientists in the past have offered two possible theories — first, they believe that the deposition of energy from the host star caused the inflation; second, they think it is because of the inhibited cooling of the planet.

The authors of the paper suggest that the new inflated hot Jupiter may be related to the fast increase of luminosity of its star as the planet evolves outside the main sequence. More so, they also concluded that the planet could be a sign that other inflated planets are found orbiting low luminous red giant stars.

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Four New Hot Jupiters

Earlier this year, The Universities Space Research Association's (USRA) Lunar and Planetary Institute reported that four new hot Jupiters were discovered in the Milky Way galaxy.

These four new exoplanets are called NGTS-15b, NGTS-16b, NGTS-17b, and NGTS-18, which were found by an international team of astronomers using the Next Generation Transit Survey telescope and are said to be 2,500 and 3,500 light-years away from Earth.

Like any hot Jupiter exoplanet, they are massive exoplanets with short orbital lengths, experience temperatures of around 1832°F (1000°C), and orbits close to their host star.

Based on their findings, three out of four of the new hot Jupiters, namely NGTS-16b, NGTS-17b, and NGTS-18, could be between 8-12 billion years old, which means they are 3-7 billion years older than Earth.

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