According to a new study accepted for publication in the Astrophysical Journal, stellar astronomers have located an adolescent star similar to our Sun that is surrounded by a number of small Pluto-like protoplanets. The researchers say this new data will provide useful insights in to the formation of our solar system.
Details on the discovery of protoplanets
The astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA) to detect a family of Pluto-size objects circling an adolescent version of our own Sun based on high levels of dust surrounding the star.
The researchers undertook detailed observations of the protoplanetary disk surrounding the star HD 107146, and discovered a surprising increase in the concentration of dust grains in the outer reaches of the disk. This concentration of dust grains begins around 13 billion kilometers from the host star, and is thought to be the result of Pluto-size protoplanets orbiting in the disk causing smaller objects to collide and create dust.
The star HD 107146 is around 90 light-years from Earth towards the constellation Coma Berenices. Astronomers believe it is close to 100 million years old. The next stage of the project involves observations with ALMA’s new long baseline, high resolution capabilities, which the astronomers hope will lead to a greater understanding of the dynamics and composition of this unusual stellar object.
Statements from researchers
“The dust in HD 107146 reveals this very interesting feature—it gets thicker in the very distant outer reaches of the star’s disk,” noted Luca Ricci, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts and lead researcher on the project.
“The surprising aspect is that this is the opposite of what we see in younger primordial disks where the dust is denser near the star. It is possible that we caught this particular debris disk at a stage in which Pluto-size planetesimals are forming right now in the outer disk while other Pluto-size bodies have already formed closer to the star,” Ricci commented.
“This system offers us the chance to study an intriguing time around a young, Sun-like star,” explained ALMA Deputy Director and study coauthor Stuart Corder. “We are possibly looking back in time here, back to when the Sun was about 2 percent of its current age.”