Sharjah: The Sharjah Astronomical Observatory (SAO) at Sharjah Academy for Astronomy, Space Sciences and Technology (SAASST) in the University of Sharjah has monitored and analysed the exoplanet HAT-P-9b this month as part of its periodic observations of various exoplanets.
Planetary objects orbiting other stars beyond our solar system are called ‘exoplanets’ and they come in a variety of sizes — from gas giants that are larger than Jupiter to smaller and rocky planets like the Earth or Mars. The first exoplanets were discovered in the 1990s and since then thousands have been identified using various detection methods.
The Sharjah Astronomical Observatory started monitoring exoplanets since 2018. The results of its observations are published periodically on astronomical research websites. His Highness Dr Sheikh Sultan bin Muhammad Al Qasimi, Member of the Supreme Council, Ruler of Sharjah and President of the University of Sharjah, founded SAASST as a scientific institution to increase public awareness and knowledge on astronomy, space sciences and technology.
Exoplanet HAT-P-9b is located in the constrictor constellation of stars at a distance of 1,500 light-years (a light-year is equivalent to around 9.46 trillion kilometres) from the Sun. This planet was discovered in 2008 through the technique of transit photometry using the Wide Angle Search for Planets (WASP) programme. Researcher Mohammed Fadil Talafha, an astronomer who specialises in observing the exoplanets, said HAT-P-9b is similar to Jupiter. “It has a mass of 78 per cent of the mass of Jupiter, but it is on the other hand larger, equivalent to 140 per cent of the size of Jupiter, and this means that it is less dense,” Talafha noted.
He elaborated: “Due to its size being close to the size of Jupiter, it is included in the series of exoplanets called Hot Jupiters. Despite its large size, HAT-P-9b is very close to its sun — the distance between it and its star does not exceed eight million kilometres. If we compare it to Earth, whose distance from the Sun reaches 150 million kilometres, then it is considered very close to the host star. The temperature of this type of exoplanet reaches 1,000 Kelvin, hence the name Hot Jupiters.”
Prof Mashhoor Al Wardat, vice-general director of SAASST for Academic Affairs and Sharjah Astronomical Observatory, said: “The SAO plays an important role in disseminating scientific information and supporting various research projects such as observing galaxies and binary stars, studying variable stars, and determining the age of star groups. Students and enthusiasts of space and astronomy also frequent the Observatory to learn more about these fields,” he added.
Talafha explained the observation of planets is done when they are in transit. “That is the time when the apparent magnitude of the star decreases slightly due to the occultation of the planet in a process known to astronomers as transit photometry.”
What are exoplanets
Planetary objects orbiting other stars are called exoplanets. They come in various sizes, ranging from gas giants larger than Jupiter, to small and rocky planets about the size of Earth or Mars. They can be hot enough to melt metals or be locked in deep freezers. They can orbit their stars so tightly that a “year” lasts only a few days and they can also orbit two suns at once. Some exoplanets are called rogue planets or sunless rogues because they are untethered to any star and they wander through the galaxy in permanent darkness.