The four giant planets, named HATS-74Ab, HATS-75b, HATS-76b and HATS-77b, revolve around early M dwarfs (red stars) and K-dwarfs (orange color), with stellar masses in the range of 0.6- 0.65 M.
According to the study, HATS-74Ab It is about the size of Jupiter, but it is 46 percent more massive than the largest planet in the solar system. It orbits its host star every 1.73 days, at a distance of 0.024 AU from it, and has an equilibrium temperature of 895 K.
The parent star is about 11 billion years old, has a radius of about 0.57 solar radii, a mass of about 0.6 solar masses, and has an effective temperature of 3777 K.
Observations show that HATS-74Ab has a stellar companion, designated HATS-74B, which is estimated to be about 80 percent less massive than the sun. The system is 934 light years distant.
With a radius of about 0.88 Jupiter radii and a mass of only 0.49 Jupiter masses, HATS-75b it is the smallest and least massive exoplanet of the four newly detected.
It has an orbital period of approximately 2.79 days and is separated by 0.032 AU from its parent star. Astronomers have calculated that the equilibrium temperature of the planet is 772.3 K.
At a distance of about 637 light years from Earth, its host HATS-75 is nearly 15 billion years old, with a radius of 0.58 solar radii. Its mass is estimated to be 0.6 solar masses. The star has an effective temperature at a level of 3790 K.
The third of the exoplanets, HATS-76b, orbits its host every 1.94 days, at a distance of 0.026 AU, and turns out to be the hottest planet in the newly discovered quartet, with an equilibrium temperature of 939.8 K.
This exoplanet is approximately 2.63 times more massive than Jupiter and its radius is estimated to be approximately 1.08 Jupiter radii.
HATS-76 has a mass of 0.66 solar masses, a radius of 0.62 solar radii, and an effective temperature of approximately 4,016 K.
Its star, located 1,271 light-years away, is relatively young compared to the other three hosts described in the paper: the age is estimated to be 4.6 billion years.
…and a quarter
HATS-77b it is about 16 percent larger and 37 percent more massive than Jupiter. The exoplanet’s orbital period is almost 3.09 days and it orbits its parent star at a distance of about 0.036 AU.
The equilibrium temperature of HATS-77b was found to be 828.3 K. The stellar host is 12.1 billion years old, is approximately 35 percent smaller and less massive than the sun, and its effective temperature is measured at 4071 K. The distance to this planetary system is estimated at 1,349 light years.
Six telescopes involved
The four objects were discovered using the data-based transit method of the HATSout photometric study, a network of six astrograph telescope systems located in South America, Africa and Australia.
These telescopes are designed to detect transiting extrasolar planets orbiting relatively bright stars visible from the southern hemisphere. Since its launch in 2009, the network has already detected dozens of transiting exoplanets.
After this detection, the planetary nature of these signals was confirmed by follow-up observations using NASA’s Transiting Exoplanet Reconnaissance Satellite (TESS) and other ground-based facilities.
HATS-74Ab, HATS-75b, HATS-76b and HATS-77b: Four Transiting Giant Planets around K and M Dwarfs. A. Jordán et al. ArXiv:2112.01928v1[astro-ph.EP
Eddie is an Australian news reporter with over 9 years in the industry and has published on Forbes and tech crunch.