Citizen scientists help discover record-breaking exoplanet in binary star system

A team of astronomers and citizen scientists has discovered a planet in the habitable zone of an unusual star system containing two stars and possibly another exoplanet. Planet hunters discovered the Neptune-like planet when it passed in front of its parent star, temporarily dimming the star’s light, similar to a solar eclipse on Earth. This “transit method” typically involves a planet having a close orbit, since it is likely to follow a path that passes between Earth and its host star, and as it follows such a path, it is likely to move into a position that blocks light. The planet is identified. For this reason, this newly discovered planet is thought to be unusually far away. The planet takes 272 days to orbit its star. Additionally, this star is currently the brightest star known to have a transiting planet in its habitable zone, where liquid water can exist. Subsequent observations of the system revealed further peculiarities. The star is also orbited by an unidentified second planet with an orbital period of 34 days, and perhaps most interestingly, by another star. This unique system represents a valuable data point for scientists seeking to understand how planets in multistar systems form and remain in stable orbits. The researchers plan to publish their findings in the Astrophysical Journal on April 30th. “Finding planets in multi-star systems is critical to understanding how different planets are made from the same material,” said study lead author Nora, a researcher at the Flatiron Institute Center for Computational Astrophysics in New York City.・Mr. Eisner says. Systems of stars and planets are formed from clouds of gas and dust. When a star forms next to another star, the pair can form a binary system. “It’s very interesting that we discovered this,” Eisner said, because it’s estimated that planets form in binary star systems half as likely as in single star systems. The newly discovered planet was officially called TOI 4633 c, but was given the nickname Percival (after a character from the Harry Potter series). The scientists were first identified by citizen scientists scrutinizing data collected by NASA’s Transiting Exoplanet Survey Satellite (TESS). The Planet Hunters TESS program allows anyone with a computer connected to the Internet to search for undiscovered planets in TESS data. “Every time I spot a possible passage, my heart beats faster and my excitement increases tremendously,” says Simon, a Danish citizen scientist who has been volunteering with Planet Planet since 2018. His Bentsen says. “We are very happy to have contributed to the discovery of a new system. We hope that the new planet will contribute to our understanding of planet formation and answer other interesting questions about planets.” Citizen scientists help astronomers sort through massive datasets that are too large for researchers to analyze alone. To date, this project has involved more than 43,000 volunteers from 90 countries and helped catalog approximately 25 million objects. Citizen scientists are especially valuable in the search for large orbiting exoplanets, which are difficult to identify with computers. “The human brain has a truly amazing ability to recognize patterns and filter out noise,” says Eisner, Planet Hunters TESS principal investigator. “Our algorithms have a hard time identifying these longer-period planets, but citizen scientists can’t.” After 15 citizen scientists identified a possible planet, Eisner and her team decided to take a closer look. Tracking the star’s radial velocity, looking for small fluctuations in the star’s motion that reveal the gravity of a nearby companion star, revealed the possibility of a second planet near the star. Additional images and archival data showed that what scientists initially thought was a single star was actually two. Her two orbiting stars are now so close that they cannot be distinguished individually from any vantage point on Earth. However, archival observations of the star collected over the past 119 years have shown that the system is actually a binary pair. This new exoplanet has the second-longest orbit of any planet discovered using TESS data, and is one of only five with an orbital period of more than 100 days. “This planet is remarkable in many ways,” Eisner said. “It’s notable for its orbit, it’s notable because it’s in the habitable zone, it’s notable because it orbits a bright star.” Although scientists believe the planet is in the habitable zone, they do not recommend it as your next interstellar vacation destination. TOI 4633 c has no solid surface, and its atmosphere is probably filled with water vapor, hydrogen, and methane. However, previous research has shown that long-period planets are likely to have moons or moons that could provide solid surfaces for the emergence of life.

“If this planet had a moon, it would probably have a solid surface, which would be a great place to find water,” Eisner said. In the future, exoplanets may become targets for exomoon detection campaigns due to their brightness and the long orbits of the planets, both of which will aid in the detection of exomoons. Scientists would like to learn more about this system, but it will be at least 30 years before the two stars are far enough apart to determine the system’s exact composition. Determining whether the planets orbit the same star or different stars could help us understand how long such star systems can remain stable. It could also help scientists better predict the discovery of new exoplanets. In fact, nearly half of all Sun-like stars live in multistar systems.

source: https://dx.doi.org/10.3847/1538-3881/ad1d5c