Astronomers from the Harvard-Smithsonian Center for Astrophysics (CfA) and elsewhere have reported the discovery of a new ‘hot Jupiter’ exoplanet orbiting a rapidly rotating F-type star. The newly discovered alien world, called TOI-4641 b, may be almost four times larger than Jupiter. The finding was detailed in an article published on the preprint server on December 7 arXiv.

In general, hot Jupiters are gas giant planets with rotation periods between 10 and 200 days. This makes them challenging targets for transit detection and subsequent radial velocity studies compared to their shorter-orbit counterparts known as hot Jupiters.

Now a team of astronomers led by CfA’s Allison Bierila has found a new such exoplanet. Using NASA’s Transiting Exoplanet Search Satellite (TESS), which scans the entire sky looking for transiting extrasolar worlds, they identified a transit signal in the light curve of TOI-4641, a bright and rapidly rotating F star. (estimated rotation speed is approximately 86.3 km/h). The planetary nature of this signal was confirmed by subsequent photometric and spectroscopic observations.

“An exoplanet candidate orbiting TOI-4641 with period 22.1d was identified in light curves containing data from Sector 43 in the SPOC and QLP pipelines,” the researchers wrote in the paper.

The newly discovered planet has a radius of approximately 0.73 Jupiter radii and its maximum mass is calculated to be 3.87 Jupiter masses. Observations show that TOI-4641 b orbits its host star every 22.09 days in a precise orbit at a distance of approximately 0.173 AU. Therefore, TOI-4641 b is one of the longest-period planets to be described in detail, orbiting a hot, rapidly rotating star.

Located about 286 light-years away, the host star TOI-4641 (also known as TIC 436873727) has a radius of about 1.72 solar radii and is about 41% larger than the Sun. The star is estimated to be 2.69 billion years old, has a metallicity of -0.09 and an effective temperature of 6560 K.

The authors of the paper emphasized that long-period exoplanets such as TOI-4641 b could be crucial for testing the mechanisms that cause primordial bias in planetary systems; Because at such orbital distances, tidal interactions between stars and planets are thought to be very high. poor to change slope.

“Confirmation of these predictions motivates the full characterization of planets in long-period orbits around early-type stars,” the scientists concluded.

Overall, Bierila’s team proposes several mechanisms behind this discrepancy, including chaotic accretion, magnetic distortion, or changes in the spin axes of early-type stars and stars or satellite planets during the primitive phase of formation.