A gas giant 11 times the mass of Jupiter in an elliptical orbit around a baby star is providing scientists with important insights into planetary formation and evolution.
Located around 300 million light years from Earth and known as HD 106906b, the star orbits far beyond the dusty proto-planetary disk near the star, the place where planets usually form.
Discovered in 2014, the system is just 13 million years old. In contrast, our solar system is 4.6 billion years old.
“This is such a young star; we have a snapshot of a baby star that just formed its planetary system–a rare peek at the final stage of planet formation,” noted Smadar Naoz of UCLA and co-author of a paper on the findings published in Astrophysical Journal Letters.
Current planet formation theories cannot explain a planet so far from its star’s proto-planetary disk. Approximately 650 times further from its star than Earth is from the Sun, HD 106906b takes 1,500 Earth years to complete a single orbit around the star.
Researchers believe it formed in its current location beyond the disk instead of having formed within the disk and somehow migrated outward.
The planet’s orbit is highly elliptical, taking it from a position very close to the star on one side to very far on the opposite side. Due to the planet’s gravity, the disk itself has become elliptical. One side of the disk is closer to the star, so its dust is warmer, and it glows more brightly.
American and European astronomers first photographed the disk in 2016 and compare it to the Kuiper Belt in our own solar system in that it is composed of numerous small objects.
Erika Nesvold of the Carnegie Institute for Science and lead author of the study, wrote software titled Superparticle-Method Algorithm for Collisions in Kuiper Belts (SMACK) that enabled the scientists to model the giant planet’s orbit.
Without the software, that is a difficult task because the planet moves so slowly.
While other planets may be present within the disk, the model was able to re-create the disk’s shape without adding any.
Comprised of gas, dust, and ice, proto-planetary disks form during the process of star formation, when clouds of gas and dust collapse due to their own gravity.
“In our solar system, we’ve had billions of years of evolution,” emphasized Michael Fitzgerald of UCLA, also a study co-author. “We’re seeing this young system revealed to us before it has had a chance to dynamically mature.”