The star Oph IRS 48 is popular among astronomers not only because it is only 390 light-years away from Earth, but also because of the mysterious 'cashew-shaped' object that lurks near it.
Until recently the nature of the object was matter of scientific debate. But all that was about to change when Nienke van der Marel, a Ph.D. student at Leiden Observatory in the Netherlands, set his eyes on the question.
Using the famous new telescope in the Chilean desert, the Atacama Large Millimeter/Submillimeter Array, or ALMA, Marel conducted a series of observation of the star, which culminated with the release of a paper that set out to explain the nature of the mysterious object. It is a 'dust trap,' Marel concluded.
Initially Marel expressed skepticism at the strange feature, but the sharpness and sensitivity of ALMA, even without its full complement of antennas, made it clear that the "dust trap" was real.
Such a trap, or vortex or bump, of material has been theorized as a way of solving the problems of how tiny dust grains clump together for form larger dust grains, and eventually larger and larger structures to form planets. Somehow, over just a few short million years, these need to go from dust to pebbles to boulders to worlds without self-destructing first. The action of a large gas giant in the system could create such a dust trap by gravitational interactions, thus allowing a safe space for the clumps to form. Previous observations of the forming planetary system show a gap in the disk of gas and dust, indicative of a large planet that has already begun to clear out its orbit.
ALMA is especially well suited for studying the origins of things in the Universe: planets, stars, and galaxies. High in the Atacama Desert in the Chilean Andes, it sits above much of the water vapor in the atmosphere, providing a clear view through a certain window in the electromagnetic spectrum that allows such scientific questions to be answered. Where did we come from? A simple dust trap may be a part of that answer.
