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Astronomers have found two gas giant exoplanets orbiting a distant sun-like star.
Members of the NASA-funded Planet Hunters Transiting Exoplanet Survey Satellite Project, known as the TESS probe, discovered planets around a distant star called HD 152843, which is located about 352 light-years from Earth.
The star has a mass similar to the Sun, but is about 1.5 times larger and slightly brighter, according to a NASA statement.
The first planet is called HD 152843b, which is about 3.4 times larger than Earth, or about the size of Neptune, and completes an orbit around its star in about 12 days. The second planet, called HD 152843c, is 5.8 times larger than Earth and 27.5 times denser than Earth, making it a Saturn-like, or a planet between the size of Neptune and Saturn. A new study indicates that its orbital period ranges between 19 and 35 days.
“Studying them together, both at the same time, is really interesting for limiting theories on how planets form and evolve over time,” Nora Eisner, the study’s lead author and a doctoral student in astrophysics at Oxford University in the UK, said in a NASA statement.
The citizen scientists of the Planet Hunters TESS project, which is operated through the Zooniverse website, discovered three distinct transit events, in which a brief dip in a star’s brightness is recorded when a planet crosses the face of the star, blocking some of its light, in one month of observational data. From HD 152843.
Their findings were confirmed by professional astronomers who compared the data with computer models, indicating that two of the transit events came from the inner planet (HD 152843b) while the third transit came from a second outer planet (HD 152843c), according to the statement.
The astronomers also used two additional instruments, the High-Resolution Radial Velocity Planet Finder for the Northern Hemisphere at Telescopio Nazionale Galileo in Spain and the High Resolution Spectrometer at Lowell Observatory in Arizona, to confirm that the transit events were in fact caused by exoplanets, rather than other sources, such as a stellar companion. Other or passing asteroids or the motions of TESS itself.
These instruments use a technique called radial velocity to detect minute “vibrations” caused by a planet orbiting its star’s motion toward or away from Earth.
Observations from HD 152843 indicate that exoplanets are too hot and gaseous to support life as we know it on Earth. However, the study of the two new exoplanets helps scientists learn about the group of potential planets in our galaxy, according to the statement.