Latest news with #Kepler-139f
Arab Times
a day ago
- Science
- Arab Times
Astronomers discover hidden alien planet 35 times heavier than Earth
NEW YORK, July 16: Astronomers have uncovered a previously undetected alien planet, Kepler-139f, by analyzing the orbits of known planets within the Kepler-139 star system. This hidden exoplanet is about twice the mass of Neptune and 35 times the mass of Earth, taking approximately 355 days to orbit its host star. The discovery was published on May 2, 2025, in The Astrophysical Journal Letters. Kepler-139f had managed to remain elusive due to limitations in early detection methods used by NASA's Kepler Space Telescope. Kepler, which identified nearly 3,000 exoplanets over its nine-year mission, primarily detected planets that passed directly between their star and Earth, causing a brief dimming of the star's light. This allowed scientists to identify the size of these planets. However, Kepler could not detect planets that were positioned above or below the line of sight of the telescope, meaning some planets remained hidden. However, because Kepler-139 is home to multiple planets, astronomers had the opportunity to search for worlds outside of Kepler's original detection range. The system was known to contain three rocky super-Earths that transit their star, and later, a fourth gas giant was discovered. Astronomers observed gaps in the orbits of these planets, suggesting the presence of an additional, unseen world. By studying these orbital gaps in detail, scientists were able to infer the existence of Kepler-139f. "The challenge isn't in finding non-transiting planets but in identifying situations where we can deduce the location of these hidden worlds," explained Caleb Lammers, a graduate student at Princeton University and co-author of the study. "It was through precise measurements of the known planets' orbits, including radial velocity (RV) and transit timing variations (TTVs), that we could infer the existence of Kepler-139f." The RV technique measures the gravitational pull a planet exerts on its host star, helping astronomers determine the planet's mass. Additionally, TTVs—subtle variations in the timing of transits of known planets—can indicate the presence of other planets that don't transit the star themselves. Lammers and his colleague, Joshua Winn, an astrophysicist at Princeton and participating scientist on the Kepler mission, worked together to identify these gaps in the system. Using a combination of RV and TTV measurements, the pair discovered Kepler-139f nestled between the outermost super-Earth and a gas giant in the system. Kepler-139f's discovery also provided clarity on the previously puzzling density of Kepler-139c, the outermost super-Earth in the system. The earlier density readings were incorrectly influenced by the pull of the hidden planet, but with Kepler-139f identified, the team revised the data, providing more typical density values for Kepler-139c. The discovery raises the possibility that other unseen planets may be lurking in the Kepler-139 system. "There may still be other undiscovered planets in the system, especially given the prominent gap between planets b and c," said Lammers. "The challenge now is to find them." While the Kepler and TESS (Transiting Exoplanet Survey Satellite) missions have been adept at detecting planets closer to their stars—where transits are more frequent and easier to observe—planets further away with wider orbits present more difficulties. Additionally, the RV method is more effective for detecting larger, more massive planets due to their stronger gravitational influence. This bias toward larger worlds has made it harder to detect smaller, more distant planets, particularly those that don't transit their stars. To combat these challenges, astronomers are combining multiple methods—transits, RVs, and TTVs—to identify smaller, hidden planets. "It's likely that many planetary systems host unseen worlds, particularly in their outer regions," Lammers added. Looking ahead, the European Space Agency's upcoming PLATO mission, launching in 2026, will provide an even more powerful tool for detecting these hidden planets. PLATO will survey transiting planets and revisit the Kepler field, refining TTV measurements and boosting the potential for discovering more misaligned and hidden worlds. "In the near future, TTV-based planet detection is expected to accelerate significantly with the PLATO mission," Lammers concluded.
Yahoo
2 days ago
- Science
- Yahoo
Astronomers discover giant alien planet 35 times more massive than Earth hiding in a known star system
When you buy through links on our articles, Future and its syndication partners may earn a commission. Scientists have detected a hidden alien planet by examining the orbits of the known worlds in the star system, known as Kepler-139. The newfound exoplanet, called Kepler-139f, is a gigantic world roughly twice the mass of Neptune and 35 times the mass of Earth, and it takes 355 days to orbit its star, astronomers reported in a study published May 2 in The Astrophysical Journal Letters. Despite its giant size, Kepler-139f had evaded detection. That's because the initial yield of NASA's Kepler space telescope, which discovered nearly 3,000 planets in its nine years of operation, relied on worlds transiting — passing between their star and Earth. The resulting dimming of the star allowed astronomers to identify planets and calculate their size. But Kepler couldn't see planets traveling above or below the wedge of space between it and the star, so any outliers remained unseen. But if the hidden world was part of a multiplanet system, astronomers could try to find it despite its inclined orbit. Kepler-139 has three rocky transiting super-Earths; a fourth gas giant was later discovered. Gaps in their orbits suggested that other worlds might be present. Precise measurements of the orbits allowed the astronomers to infer the existence of at least one more planet. "The issue is not exactly finding non-transiting planets, but rather, finding situations in which we can deduce where the non-transiting planet is located," Caleb Lammers, a graduate student in the Department of Astrophysical Science at Princeton and co-author of the study, told by email. Kepler's initial identification of a world was often followed up by observations from the ground. Using radial velocity (RV), astronomers could measure how much a planet tugged on its star, allowing them to determine the planet's mass. RV measurements could also reveal new worlds, as happened with the outermost gas giant, Kepler-139e. At the same time, each planet is pulled by not only its star but also by other planets in the system, regardless of whether that planet can be seen from Earth. These pulls can affect how swiftly a planet transits, thus creating "transit timing variations" (TTVs). These variations in the transiting planets can reveal worlds that don't cross the star. "When you observe TTVs that cannot be attributed to the known planets, you can be fairly confident that there is an unseen body in the system," Lammers said. Lammers and his colleague Joshua Winn, a participating scientist on the Kepler team and co-author of the study, went looking for gaps in known systems. Then, they used both RV and TTV measurements to hunt for a missing world, revising existing TTVs based on the 2023 discovery of Kepler-139e. "What was different in the case of Kepler-139 is that we had precise radial velocity observations which did not conclusively point towards a new planet on their own," Lammers said. Combined with the TTVs, the observations revealed a fifth planet, Kepler-139f, tucked between the outermost super-Earth and the gas giant. The new discovery also helped to answer a question about Kepler-139e. The original reports of Kepler-139c, the outermost super-Earth, provided an unusually large density for a sub-Neptune-size planet. The discrepancy occurred because those authors didn't know about Kepler139f, so they had attributed some of its pull on its star to Kepler-139c. The new data suggest a more typical density for Kepler-139c while leaving the densities for Kepler-139d and Kepler-139b essentially unchanged. These revisions provide indirect evidence for Kepler-139f, Lammers said. There may even be other hidden worlds around Kepler-139. "It remains possible that there are other unseen planets in the system," Lammers said, pointing to the prominent gap between planets b and c. "The challenge is finding them!" Both Kepler and NASA's more recent exoplanet hunting mission, the Transiting Exoplanet Survey Satellite (TESS), were sensitive to planets orbiting closer to their star. These inner worlds were more likely to make many transits, allowing scientists to confirm the planet's existence. But transiting planets with wider orbits made only a handful of passes, so they were more challenging to observe and confirm. At the same time, the RV method tends to be biased toward larger planets, because the more massive a world is, the stronger it tugs on its star. Proximity helps; the pull of the planet is amplified to the square inverse of its distance. Thus, a planet twice as far away will have only one-fourth the gravitational pull. That's why many of the first discovered exoplanets were Jupiter-size worlds that circled their star in only a few days. RELATED STORIES —Massive new NASA exoplanet catalog unveils 126 extreme and exotic worlds —25 years of exoplanet hunting hasn't revealed Earth 2.0 — but is that what we're looking for? —The 10 most Earth-like exoplanets All of these factors make it harder to discover smaller planets that are farther away, particularly if they don't transit their star. But by combining transits, RVs and TTVs, astronomers can find smaller, hidden worlds orbiting farther from their star. "It is likely that many planetary systems host unseen worlds, especially in their outer regions," Lammers said. But soon, it will be harder for those worlds to hide. In 2026, the European Space Agency will launch its Planetary Transits and Oscillations of Stars (PLATO) mission, which will conduct its own survey of transiting planets, as well as revisit Kepler's field. In providing additional transit times for planets detected by Kepler more than a decade later, PLATO will improve measurements of TTVs to enable the discovery of more misaligned worlds. "In the coming years, the TTV planet detection technique will probably be accelerated dramatically by the PLATO mission," Lammars said.
