Discovery of a new super-hot Jupiter exoplanet

An international team of astronomers has detected a new ultra-hot extrasolar planet Jupiter using NASA’s Transiting Exoplanet Survey (TESS) satellite. The new alien world is almost twice the size of Jupiter and has a misaligned orbit. The discovery is detailed in an article published August 25 on the arXiv preprint repository.

So-called “hot Jupiters” have characteristics similar to those of the largest planet in the solar system, but have orbital periods of less than 10 days. These exoplanets have high surface temperatures because they orbit very close to their mother stars.

Now, a group of astronomers led by Samuel HC Cabot of Yale University are reporting the discovery of a new such exoplanet, which is found to have an ultra-high surface temperature. By observing a bright star designated TOI-1518 with TESS, a transit signal was identified in the light curve of this object. The planetary nature of this signal was confirmed by high-resolution tracking observations with the EXPRES spectrograph of the Lowell Discovery Telescope.

“We present the discovery of TOI-1518b, an ultra-hot Jupiter orbiting a bright star (V = 8.95). The planet in transit is confirmed using high-resolution optical transmission spectra from FAST, ”the researchers wrote in the article.

TOI-1518b has a radius of about 1.875 rays from Jupiter, while its mass is uncertain, estimated not to exceed 2.3 masses from Jupiter. Future monitoring of the radial speed of this system will impose more constraints on its mass. The planet orbits its host every 1.9 days, at a distance of almost 0.04 AU from it.

The study found that TOI-1518b has an equilibrium temperature of 2,492 K and a measured daytime light temperature of 3,237 K, suggesting that it may exhibit thermal inversion. However, further spectroscopic observations of this exoplanet are needed to confirm this.

According to the article, TOI-1518b has a very misaligned orbit, around 240.34 degrees. In trying to explain this finding, astronomers noted that in general, gas giants near hot stars are generally misaligned. The star TOI-1518 has an effective temperature of about 7300 K, is about twice the size of the sun, and its mass is estimated at 1.79 solar mass.

Research has also detected iron (Fe) in the atmosphere of TOI-1518b. The team performed an atmospheric cross-correlation analysis and found neutral iron. They pointed out that so far there have only been a handful of previous detections of iron in super-hot Jupiters.

“We looked for neutral and ionized Fe in the companion’s atmosphere by high resolution transmission spectroscopy. (…) We detect neutral iron (5.2σ), at K_p = 157 km / s and V_system = -16 km / s, adding another object to the small sample of highly irradiated gas giant planets with transmitting Fe detections, “the scientists wrote.

© 2021 Science X Network