Carbonados, also known as ‘black diamonds,’ are a far cry from the kind of diamonds that adorn a wedding ring. They’re gray to black in color, lack the beautiful crystaline structure of standard diamonds, and usually wind up being used in industrial settings for their abrasive qualities. And now we’re learning why these somewhat nondescript objects aren’t found in the usual places for diamond mining. Their origin may lie not within the Earth but in interstellar space.
Or so say Jozsef Garai and Stephen Haggerty (Florida International University) in a recently published paper. Working with researchers from Case Western, the team used infrared synchrotron radiation at Brookhaven National Laboratory to analyze carbonado samples, finding enough hydrogen to indicate an origin in hydrogen-rich interstellar space. Haggerty has, in fact, conducted earlier research showing that these diamonds are the result of supernovae explosions, and that they arrived on Earth as objects originally a kilometer or more in diameter.
The paper is Garai et al., “Infrared Absorption Investigations Confirm the Extraterrestrial Origin of Carbonado Diamonds,” Astrophysical Journal 653: L153-156 (20 December 2006), with abstract here.
Physics, abstract
physics/0608014
From: Jozsef Garai [view email]
Date (v1): Wed, 2 Aug 2006 19:58:35 GMT (152kb)
Date (revised v2): Fri, 27 Oct 2006 20:11:19 GMT (271kb)
Infrared Absorption Investigations Confirm the Extraterrestrial Origin of Carbonado-Diamonds
Authors: Jozsef Garai, Stephen E. Haggerty, Sandeep Rekhi, Mark Chance
Subj-class: Space Physics
Journal-ref: The Astrophysical Journal, 653: L153-L156, 2006
The first complete infrared FTIR absorption spectra for carbonado-diamond confirm the interstellar origin for the most enigmatic diamonds known as carbonado. All previous attempts failed to measure the absorption of carbonado-diamond in the most important IR-range of 1000-1300 cm-1 (10.00-7.69 micro-m.) because of silica inclusions. In our investigation, KBr pellets were made from crushed silica-free carbonado-diamond and thin sections were also prepared. The 100 to 1000 times brighter synchrotron infrared radiation permits a greater spatial resolution. Inclusions and pore spaces were avoided and/or sources of chemical contamination were removed. The FTIR spectra of carbonado-diamond mostly depict the presence of single nitrogen impurities, and hydrogen. The lack of identifiable nitrogen aggregates in the infrared spectra, the presence of features related to hydrocarbon stretch bonds, and the resemblance of the spectra to CVD and presolar diamonds indicate that carbonado-diamonds formed in a hydrogen-rich interstellar environment. This is consistent with carbonado-diamond being sintered and porous, with extremely reduced metals, metal alloys, carbides and nitrides, light carbon isotopes, surfaces with glassy melt-like patinas, deformation lamellae, and a complete absence of primary, terrestrial mineral inclusions. The 2.6-3.8 billion year old fragmented body was of asteroidal proportions.
http://arxiv.org/abs/physics/0608014
Spatially Resolved 3 micron Spectroscopy of Elias 1: Origin of Diamonds in Protoplanetary Disks
Authors: M. Goto (1), Th. Henning (1), A. Kouchi (2), H. Takami (3), Y. Hayano (3), T. Usuda (3), N. Takato (3), H. Terada (3), S. Oya (3), C. Jäger (4), A. C. Andersen (5) ((1) MPIA, (2) Institute of Low Temperature Science, Hokkaido University, (3) Subaru Telescope, (4) Institute of Solid State Physics, Friedrich-Schiller-Universitaet Jena, (5) Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen)
(Submitted on 13 Nov 2008)
Abstract: We present spatially resolved 3 um spectra of Elias 1 obtained with an adaptive optics system. The central part of the disk is almost devoid of PAH emission at 3.3 um; it shows up only at 30 AU and beyond. The PAH emission extends up to 100 AU, at least to the outer boundary of our observation. The diamond emission, in contrast, is more centrally concentrated, with the column density peaked around 30 AU from the star.
There are only three Herbig Ae/Be stars known to date that show diamond emission at 3.53 um. Two of them have low-mass companions likely responsible for the large X-ray flares observed toward the Herbig Ae/Be stars. We speculate on the origin of diamonds in circumstellar disks in terms of the graphitic material being transformed into diamond under the irradiation of highly energetic particles.
Comments: 7 pages, 4 figures, Accepted for publication in the Astrophysical Journa
Subjects: Astrophysics (astro-ph)
Cite as: arXiv:0811.2220v1 [astro-ph]
Submission history
From: Miwa Goto [view email]
[v1] Thu, 13 Nov 2008 21:00:04 GMT (291kb)
http://arxiv.org/abs/0811.2220