A team of astronomers and citizen scientists has discovered a planet in the habitable zone of an unusual star system, including two stars and potentially another exoplanet.
The star is also orbited by a still unconfirmed second planet with a 34-day orbit and, perhaps most interestingly, another star.
When a star forms alongside another star, the pair can form a binary star system.
The citizen scientists help the astronomers sort through the enormous datasets, which are far too large for researchers to analyze on their own.
Citizen scientists are particularly invaluable in finding long-orbit exoplanets because these objects are hard for computers to identify.
“While our algorithms struggle to identify these longer-period planets, the citizen scientists don’t.”
After 15 citizen scientists flagged the possible planet, Eisner and her team decided to take a closer look.
Confirming whether the planets orbit the same star or different ones could help improve our understanding of how long such systems can remain stable.
A planet in the habitable zone of an unusual star system, which also includes two stars and possibly another exoplanet, has been found by a group of citizen scientists and astronomers.
When the Neptune-like planet passed in front of its host star, the light from the star momentarily decreased, much like during an eclipse of the sun. This was visible to the planet hunters. Using the “transit method,” planets with tight orbits are typically identified because they are more likely to travel on paths that place them between Earth and their host star and to move into positions where they block light more frequently. As a result, this recently found planet is thought to be exceptionally far away, taking 272 days to orbit its star.
Moreover, the star is currently by far the brightest known to support a transiting planet in the habitable zone—the region where liquid water can exist.
Additional anomalies were discovered during subsequent observations of the system. In addition, there appears to be another star and, possibly most intriguing of all, a second, as-yet-unconfirmed planet circling the star, both with orbits of 34 days. For researchers attempting to comprehend how planets form and maintain stable orbits in multi-star systems, the unusual system offers an invaluable data point. On April 30, the researchers publish their findings in The Astrophysical Journal.
According to study lead author Nora Eisner, a research fellow at the Center for Computational Astrophysics at the Flatiron Institute in New York City, “finding planets in multi-star systems is crucial for our understanding of how you can make different planets out of the same material.”.
Clouds of gas and dust start to group together to form systems of stars and planets. A binary star system can form when two stars form next to each other. Eisner states that “it’s quite exciting that we found this one.” Planets are thought to form in binary star systems half as frequently as in single-star systems. “.”.
Citizen scientists sorting through data gathered by NASA’s Transiting Exoplanet Survey Satellite (TESS) initially discovered the newly discovered planet, officially named TOI 4633 c, but given the nickname Percival by the scientists (after a character from the “Harry Potter” book series). Anyone with a computer and an internet connection can search the TESS data for undiscovered planets using the Planet Hunters TESS program.
Simon Bentzen, a Danish citizen scientist who has volunteered with Planet Hunters TESS since 2018, says, “Every time I spot a possible transit, I can feel my heart beat faster and my excitement rise extensively.”. That I contributed to the creation of the new system makes me very happy. My aspiration is that the newly discovered planets will enhance our comprehension of planet formation and provide answers to additional fascinating planetary inquiries. “.
The massive datasets are much too big for researchers to examine alone, so the citizen scientists assist the astronomers in sifting through them. Over 43,000 volunteers from 90 countries have contributed to the project’s cataloging of about 25 million objects so far. Because long-orbit exoplanets are difficult for computers to identify, citizen scientists are especially helpful in this search.
Planet Hunters TESS principal investigator Eisner says, “The human brain has a really incredible ability to recognize patterns and to filter out noise.”. “While our algorithms find it difficult to recognize these planets with longer periods, citizen scientists are able to do so.”. ****.
Eisner and her colleagues made the decision to investigate further after 15 citizen scientists raised the potential planet’s notice. A possible second planet was discovered near the star by radial velocity monitoring, which searched for minute oscillations in the star’s motion that would indicate the gravitational pull of nearby companions.
What the scientists initially believed to be a single star turned out to be two, according to additional photos and historical data. Right now, it is impossible to tell the two co-orbiting stars apart from Earth because of their proximity. Archival observations of the star gathered over the previous 119 years, however, demonstrated that the system is in fact a pair of binary stars.
The newly discovered exoplanet is one of only five planets with orbits longer than 100 days, and it has the second-longest orbit of any planet found with TESS data. According to Eisner, “This planet is remarkable in many ways.”. It is amazing in its orbit, exceptional for being in the habitable zone, and exceptional for circling a luminous star. “.
Although the planet appears to be in the habitable zone, scientists do not recommend visiting it for your next interstellar travel. Water vapor, hydrogen, and methane are likely abundant in the atmosphere of TOI 4633 c, which lacks a solid surface. But prior research has indicated that long-period planets are more likely to have moons or satellites, which could provide solid surfaces on which life could establish itself.
Eisner notes that “if this planet had a moon, that moon would probably have a solid surface, which could then be a great place to find water.”. Given the system’s brightness and the planet’s extended orbit, which are both advantageous for exomoon detection, the exoplanet may be the focus of exomoon detection campaigns in the future.
It will take at least 30 years for the two stars to get far enough apart for scientists to figure out the precise structure of the stellar system, despite their eagerness to learn more about it. Our knowledge of how long such systems can remain stable may be enhanced by confirming whether the planets orbit different stars or the same one.
Additionally, it might aid in improving the forecasts made by scientists in search of new exoplanets. It’s true that a large majority of sun-like stars reside in systems with multiple stars.
According to Eisner, “if we could constrain the planets’ orbits, that would really offer a stepping stone to open up our understanding of exoplanet formation.”. Additionally, it might one day enable us to infer potential planets orbiting a star system from observations of its properties. “.”.
Eisner advises anyone interested in volunteering with Planet Hunters TESS to visit the website.
