Astronomers discovered a new exoplanet through data from the Gaia spacecraft, which identified a kink in the motion of a star named HIP-99770, indicating the existence of a nearby planet. Follow-up observations led to the first-ever direct image of an exoplanet through precision astrometry or tracking the star's movement, combined with direct imaging.
The exoplanet was named HIP-99770b, which is a significant discovery that could help refine the understanding of exoplanet formation and composition. The gas giant is located 320 light-years away and is 10 times more massive than Jupiter. Researchers noted that its discovery highlights the potential of combining techniques for detecting exoplanets that may result in more discoveries in the future.
First Exoplanet Discovered Through Direct Imaging, Precision Astrometry Using Subaru Telescope
First Exoplanet Discovered Through Direct Imaging and Precision Astrometry
Direct imaging allows astronomers to see an exoplanet and study its atmosphere, but it has only yielded around 20 exoplanet discoveries over the past 15 years. Meanwhile, indirect planet detection methods determine a planet's existence through its effect on the star it orbits, allowing for detailed measurements of mass and orbit.
The study, titled "Direct Imaging and Astrometric Detection of a Gas Giant Planet Orbiting an Accelerating Star" published in Science, reports the first exoplanet discovered through a combination of direct and indirect methods was made using data from the Subaru Telescope in Hawaii and space telescopes from the European Space Agency (ESA).
As per Science Daily, an exoplanet is defined as a planet located outside of the Solar System which orbits around a different star. Direct imaging is used to study an exoplanet's atmosphere by observing its light. However, this method has only resulted in around 20 exoplanet discoveries in the last 15 years.
The Subaru Telescope based in Hawaii and space telescopes from the European Space Agency (ESA) was key to the recent discovery. Combining direct imaging and precision astrometry in examining a planet's position results in a more comprehensive understanding of the exoplanet.
Although indirect planet detection methods have been responsible for most exoplanet discoveries in recent times, precision astrometry, one of these methods, made it easier to identify planets for direct imaging. The team was then able to use this information in conjunction with direct imaging to discover the first exoplanet using both methods.
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More About HIP-99770b
According to Science Alert, HIP-99770b is an exoplanet that orbits a star twice the mass of the Sun. It is located at a distance of 17 astronomical units, which is more than three times Jupiter's distance of 5 astronomical units from the Sun, and a little closer than Uranus's distance of 19.8 astronomical units.
Astronomers found that the exoplanet is warmer, less cloudy, and made of a mixture of water and carbon monoxide. The star has an icy debris disk orbiting at a distance of 150 astronomical units similar to the Kuiper Belt in the Solar System.
Furthermore, it has a radius 1.05 times that of Jupiter, and its mass is between 14 and 16 times greater than the ice giant in the Solar System. Despite its distance, it receives approximately the same amount of radiation as Jupiter due to HIP-99770 being brighter than our Sun.
The researchers said they are planning on further studying the exoplanet to see what else can be discovered from direct imaging. These findings are part of their Keck and Subaru imaging program, which uses astrometry to select targets.
HIP-99770b is the first successful outcome of the combined technique, and they expect to make many more discoveries from analyzing the Gaia-Hipparcos data that has approximately 50 candidate stars. The team will be announcing more of their findings later this year and next year.
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