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Science & Nature

Graduate student discovers youngest transiting planet ever聽

Identified by 色中色astronomer Madyson Barber, the 鈥渂aby鈥 planet is 3 million years old and roughly the size of Jupiter.

An artistic interpretation of a new planet, next to a headshot of Madyson Barber
An artistic interpretation of the IRAS 04125+2902 (TIDYE-1) system. Young stars like this are covered in starspots 鈥 regions cooler than the surrounding stellar surface. The inner disk is depleted, leaving an intact outer disk that forms a donut-like structure around the host star. The outer disk is nearly face-on, in contrast to the edge-on planet orbit around the host star. This allows for an unobstructed view of the system. If the disk were also edge-on, it would block the planet and host star, preventing the discovery. (NASA/JPL-Caltech/R. Hurt, K. Miller (Caltech/IPAC))

色中色graduate student Madyson Barber has spent the last three years scanning the universe for newborn planets 鈥 one star cluster at time.聽聽

The work began as research for Barber鈥檚 thesis project in the College of Arts and Sciences鈥 , but it has since led to a major finding. Earlier this year, Barber identified the youngest transiting planet ever discovered.聽聽

The planet, named TIDYE-1b, is roughly the size of Jupiter and is an estimated 3 million years old. To put that age into perspective: If Earth were a 50-year-old person, TIDYE-1b would be a 2-week-old infant.聽聽

Barber found the planet under the direction of UNC-Chapel Hill associate professor , who leads a team of nine students in his in Phillips Hall. On Nov. 20, the international science journal Nature published the 38-author paper titled 鈥淎 Giant Planet Transiting a 3Myr Protostar With a Misaligned Disk,鈥 with Barber and Mann as lead authors.聽聽

Barber is still wrapping her mind around the magnitude of her discovery.聽

鈥淚鈥檝e been looking for new planets for a while now, and it felt like we weren鈥檛 finding anything,鈥 Barber said. 鈥淭his was one of the first planets that popped out of our pipeline. It still feels really weird. 鈥榃eird鈥 is the best word I have for it.鈥澛犅

Barber has been part of the Young Worlds Lab since 2020, when she was still an undergraduate.聽聽

Mann founded the lab with the goal of better understanding the formation of young planets and how they evolve over time. To find young planets, Mann, Barber and the team observe the light emitted by stars. If the light dims, it could be the sign of a transiting planet.聽聽

鈥淲hen we鈥檙e looking for transits, we’re looking at the star鈥檚 brightness over a period of time,鈥 Barber said. 鈥淲hen the planet comes in front of the star, we see a little dip in that brightness, because it鈥檚 blocking some of the star. So we鈥檙e looking for those repeated dips in the light curve.鈥澛

Astronomers have found dozens of transiting planets in the 10- to 40-million-year-old range, but younger planets had been elusive before Barber鈥檚 discovery. A key reason why young planets are difficult to find is due to the thick, view-blocking protoplanetary disks that form around stars in the first 5 to 10 million years of life.聽聽

However, the star that TIDYE-1b orbits has a misaligned disk, leaving the planet visible. The origin of that misalignment is still a mystery, and one that baffles astronomers.聽聽

鈥淧lanets form in disks, and what you鈥檇 expect is the star, the planet and the disk to all be aligned,鈥 Mann said. 鈥淭he really weird thing about this system is the planet has an orientation that agrees with the star, but the disk is way off. It鈥檚 something like 60-plus degrees off.聽

鈥淓very astronomer looks at that and goes, 鈥楻eally? That鈥檚 weird.鈥 Because, you know, every astronomer is thinking about angular momentum, just from intro physics, and they know that shouldn鈥檛 happen.鈥澛

Clearly, there鈥檚 more to learn about TIDYE-1b and its origins. Barber is taking the lead on further observations, with a trip planned for the W.M. Keck Observatory in Hawaii. Mann and Barber are also proposing for time with the James Webb Space Telescope 鈥 the largest in space.聽聽

Studying young planets like TIDYE-1b is essential to understanding how planets form and evolve.聽聽

鈥淭his proves that we can find these young systems,鈥 Barber said. 鈥淪o now we know we should be looking for more, and if we can make a population of these young systems, then we can draw even more conclusions.鈥澛