NASA’s TESS Space Telescope Detects New ‘Warm Jupiter’ Exoplanet Surrounding a Rapidly Rotating Star With Unusual Orbit

Recently, scientists have expanded the catalog of known exoplanets with a remarkable find. A warm alien world surrounds a star resembling our Sun but in a strange orbit.

(Photo: Wikimedia Commons/ ESO/M. Kornmesser)

New 'Warm Jupiter'

The discovery was made by astronomers from the Harvard-Smithsonian Center for Astrophysics (CfA) and is discussed in the paper "TOI-4641b: An Aligned Warm Jupiter Orbiting a Bright (V=7.5) Rapidly Rotating F-star". The newly found exoplanet, designated TOI-4641 b, is estimated to be almost ten times larger than Earth.

TOI-4641 b was discovered using NASA's Transiting Exoplanet Survey Satellite (TESS). The space satellite uses wide-field cameras to detect planets by the dip in light they cause as they transit the face of their star.

This observation was followed up two more times using the ground-based facilities of the TESS Follow-up Observing Program. The planet's presence was confirmed by detecting its transit across TOI-1859, a rapidly rotating star about 1.3 times the size of our Sun and located around 730 light-years from our Solar System.

It was also found that the warm Jupiter-like world takes around 64 Earth days to orbit its parent star. The exoplanet is slightly smaller than Jupiter, with an estimated diameter of about 78,000 miles (126,000 kilometers).

Warm Jupiters refer to gas giant planets with orbital periods between 10 and 200 days. Compared to their shorter-orbit counterparts called 'hot Jupiters,' warm Jupiters are more challenging targets for transit detection and follow-studies on radial velocity.

Highly-Eccentric Orbit

Experts have not yet determined the mass of TOI-1859 b, but they discovered that its orbit is flattened, highly eccentric, and misaligned about its star. It was hypothesized that this unusual orbit could result from its interactions with other planets in its cosmic neighborhood.

This orbit demonstrates characteristics consistent with the theory that multiple gas giants form around metal-rich stars and then migrate to outer regions of the planetary systems. The migration, which resulted from the gravitational interactions between these planets, can also leave the gas giants close to their host stars with misaligned and eccentric orbits like that of TOI-1859 b.

The research team also assumed that the planet's orbit might have been caused by an encounter with a "brown dwarf" in its planetary system. Brown dwarfs are described as "failed stars" since they are more massive than gas giants but are too small to become stars. Their discovery provides a better insight into the dividing mass line between stars and planets.

The interaction that left TOI-1859 b in its current orbital state is also responsible for placing the planet at a distance of around 30 million miles (49 million kilometers) from its host star. This proximity likely gives it a warmer surface temperature, making it a "warm Jupiter."

The researchers plan to investigate the planetary surroundings of TOI-1859 b further to discover the real cause of its strange orbit. This will include the search for other planets or brown dwarfs around the dwarf star TOI-1859. They also plan to consider the effect of its host star's temperature, potentially revealing more information about warm Jupiters.