Green Bank Observatory | 2018 Jun 11
Nanoscale gemstones source of mysterious cosmic microwave light
Some of the tiniest diamonds in the universe – bits of crystalline carbon hundreds of thousands of times smaller than a grain of sand – have been detected swirling around three infant star systems in the Milky Way. These microscopic gemstones are neither rare nor precious; they are, however, exciting for astronomers who identified them as the source of a mysterious cosmic microwave “glow” emanating from several protoplanetary disks in our galaxy.
For decades, astronomers have puzzled over the exact source of a peculiar type of faint microwave light emanating from a number of regions across the Milky Way. Known as anomalous microwave emission (AME), this light comes from energy released by rapidly spinning nanoparticles – bits of matter so small that they defy detection by ordinary microscopes. (The period on an average printed page is approximately 500,000 nanometers across.) ...
Until now, the most likely culprit for this microwave emission was thought to be a class of organic molecules known as polycyclic aromatic hydrocarbons (PAHs) – carbon-based molecules found throughout interstellar space and recognized by the distinct, yet faint infrared (IR) light they emit. Nanodiamonds -- particularly hydrogenated nanodiamonds, those bristling with hydrogen-bearing molecules on their surfaces -- also naturally emit in the infrared portion of the spectrum, but at a different wavelength.
A series of observations with the National Science Foundation’s Green Bank Telescope (GBT) in West Virginia and the Australia Telescope Compact Array (ATCA) has -- for the first time -- homed in on three clear sources of AME light, the protoplanetary disks surrounding the young stars known as V892 Tau, HD 97048, and MWC 297. The GBT observed V892 Tau and the ATCA observed the other two systems. ...
Anomalous Microwave Emission from Spinning Nanodiamonds around Stars - J.S. Greaves et al
- Nature Astronomy (online 11 Jun 2018) DOI: 10.1038/s41550-018-0495-z