Anomalous microwave emission from spinning nanodiamonds around stars
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Authors
Greaves, JS
Scaife, AMM
Frayer, DT
Green, DA
Mason, BS
Smith, AMS
Publication Date
2018Journal Title
Nature Astronomy
ISSN
2397-3366
Publisher
Springer Nature
Volume
2
Pages
662-667
Language
eng
Type
Article
This Version
AM
Metadata
Show full item recordCitation
Greaves, J., Scaife, A., Frayer, D., Green, D., Mason, B., & Smith, A. (2018). Anomalous microwave emission from spinning nanodiamonds around stars. Nature Astronomy, 2 662-667. https://doi.org/10.1038/s41550-018-0495-z
Abstract
Several interstellar environments produce 'anomalous microwave emission'
(AME), with brightness peaks at tens-of-gigahertz frequencies. The
emission's origins are uncertain -- rapidly spinning nanoparticles could
emit electric-dipole radiation, but the polycyclic aromatic hydrocarbons
that have been proposed as the carrier are now found not to correlate
with Galactic AME signals. The difficulty is in identifying co-spatial
sources over long lines of sight. Here we identify AME in three
proto-planetary discs. These are the only known systems that host
hydrogenated nanodiamonds, in contrast to the very common detection of
polycyclic aromatic hydrocarbons. Using spectroscopy, the nanodiamonds
are located close to the host stars, at physically well-constrained
temperatures. Developing disc models, we reproduce the emission with
diamonds 0.75--1.1 nm in radius, holding <= 1-2% of the carbon budget.
Ratios of microwave emission to stellar luminosity are approximately
constant, allowing nanodiamonds to be ubiquitous but emitting below
detection thresholds in many star systems. This result is compatible
with the findings with similar-sized diamonds found within Solar System
meteorites. As nanodiamond spectral absorption is seen in interstellar
sightlines, these particles are also a candidate for generating
galaxy-scale AME.
Keywords
Early solar system, interstellar medium, stars
Sponsorship
European Research Council (307215)
Identifiers
External DOI: https://doi.org/10.1038/s41550-018-0495-z
This record's URL: https://www.repository.cam.ac.uk/handle/1810/280694
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http://www.rioxx.net/licenses/all-rights-reserved
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