The universe is no place for an infant world. As youngins, planets are shrouded by the orbiting disk of material from which they formed, hiding them from view. But a research team’s analysis of a large planet orbiting a 3 million-year-old star offers a rare view of a newly-formed world because, as it turns out, it’s just a big baby.
The planet is the youngest so far detected by the dominant method of planet detection, according to the researchers, who designated it IRAS 04125+2902 b—a big name for a cute little guy. Astronomers spotted the baby planet because its outer debris disk is severely warped, exposing it to the prying eyes of space telescopes. The team’s discovery is detailed in a paper published in Nature, and challenges current theories of how planets form.
The young alien world is about the same age as its parent star. It likely formed around 3 million years ago, which is relatively young in cosmic years (Earth, by comparison, is 4.5 billion years old). The baby planet is located in the Taurus Molecular Cloud, a stellar nursery littered with newborn stars which lies around 450 light-years away from Earth. It circles its star at a close distance, completing one full orbit in just under nine days.
Despite being young, it’s still a big boy, about 10 times as wide as Earth with a mass about one-third that of Jupiter. That means it likely has an inflated atmosphere that will shrink over time as it’s still in the process of formation. In time, the planet could become a gaseous mini-Neptune or a rocky super-Earth, according to the paper.
The Transiting Exoplanet Survey Satellite (TESS) spotted the baby planet in November 2019. TESS searches for alien worlds by watching for a slight dip in a star’s light as a planet passes in front of it from the observer’s view. TESS isn’t usually in the business of catching babies, but the young star system’s warped disk made it possible for the space telescope to spot IRAS 04125+2902 b.
The star system’s misaligned disk remains a mystery. The disks, a rotating swirl of gas and dust that surrounds a newly formed star, usually align with a planet’s orbital plane. The baby planet’s orbit and its host star’s rotation are consistent with edge-on orientations, the team found, but the star system’s disk is tilted at a 30-degree angle. As the odd one out, the disk’s misalignment could be due to material falling from the star-forming region surrounding the system.
The baby planet offers unique insights into the early years of planetary formation, an adorable glimpse of the cosmos that we rarely get to see.
