Planet-forming disks are a natural outcome of angular momentum conservation as molecular clouds collapse to form stars. During this collapse, the clouds begin to spin faster, eventually flattening into a disk shape. These “protoplanetary disks” are thought to form planets over roughly 10 million years, after which the disk material dissipates, leaving behind a mature planetary system. It is generally expected that planets will align with the disk from which they formed. Indeed, the orderly, flat orientation of the planets in our Solar System was among the earliest clues that planets emerge from flattened protoplanetary disks.
A recent discovery, led by Madyson Barber and Andrew Mann, has unveiled a rare example of a young giant planet – IRAS 04125+2902b (also known as TIDYE-1b). This system resides in the Taurus-Auriga Molecular Cloud, a stellar nursery home to hundreds of newly formed stars. At just three million years old, this infant planet is the youngest transiting planet detected to date, roughly equivalent to a ten-day-old newborn on human timescales. The host star still retains its protoplanetary disk, further distinguishing it from other known planetary systems.
Previously, systems like TIDYE-1b were thought to be nearly impossible to detect. By three million years, it was uncertain if planets had developed to a detectable degree (for context, Earth took 10-20 million years to form). Additionally, if the disk and planet were aligned, the disk would obstruct our view. However, in this case, the inner portion of the disk is depleted, and the outer disk is tilted relative to both the planet and its host star.
The discovery of TIDYE-1b challenges current theories of planet formation timescales and the relationship between planets and their parent disks. It also offers a unique opportunity to study a planet shortly after its formation.
The results were published in the most recent edition of Nature. In addition to Madyson and Andrew, the paper is co-authored by four other members of UNC Physics and Astronomy; Andrew Boyle, Matthew Fields, Isabel Lopez-Murillo, and Pa Chia Thao, all members of the Young Worlds Lab.
Madyson Barber, a graduate student in the department of Physics and Astronomy, discovered TIDYE-1b, is lead-author on the Nature paper, and is PI of the TIDYE survey. Prior to starting graduate school, she was an undergraduate and Chancellor’s Science Scholar at UNC [left].
An artistic interpretation of the TIDYE-1b system. Young stars like this are covered in starspots—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 planet’s orbit aligns with the host star’s rotation, while the nearly face-on outer disk allows an unobstructed view of the system. If the disk were edge-on, it would block both the planet and the host. Image credit: NASA/JPL-Caltech/R. Hurt, K. Miller (Caltech/IPAC) [right]