Fullerenes and fullerene-related molecules have been proposed as explanations for unidentified astronomical features such as the intense UV absorption band at 217 nm and the enigmatic diffuse interstellar bands (DIBs), In order to shed light on the a long-standing DIB’s problem, we search high-resolution and high-quality VLT/UVES optical spectra of the hot R Coronae Borealis (RCB) star DY Cen for electronic transitions of the neutral C60 fullerene molecule and DIBs. We report the non-detection of the strongest C60 electronic transitions (e.g., those at ∼376, 398, and 402 nm). DIBs towards DY Cen are normal for its reddening; the only exception is the DIB at 628 nm (possibly also the 722 nm DIB) that is found to be unusually strong. We also report the detection of a new broad (FWHM∼2 Å) and unidentified feature centered at∼400 nm. The non detection of neutral C60 in the high-quality VLT/UVES DY Cen’s spectrum may support recent experimental work, showing that the∼7.0, 8.5, 17.4, and 18.8 micron IR features seen in sources with polycyclic aromatic hydrocarbon (PAH)-like dominated spectra have to attributed to proto-fullerenes rather than to neutral C60. In addition, the new 400 nm DIB reported here (possibly also the carriers of the classical 628 nm and 722 nm DIBs) may be related to fullerene precursors; an organic compound containing pentagonal rings. These pentagonal carbon rings are usually present in hydrogenated amorphous carbon (HAC) nanoparticles and nanotubes, suggesting that they may be intimately related with the formation process of fullerenes.
Advertised on
References
The Astrophysical Journal Letters, 2012, 759, L21
It may interest you
-
The universality of the stellar initial mass function (IMF) is one of the most widespread assumptions in modern Astronomy and yet, it might be flawed. While observations in the Milky Way generally support an IMF that is invariant with respect to the local conditions under which stars form, measurements of massive early-type galaxies systematically point towards a non-universal IMF. To bridge the gap between both sets of evidence, in this work we measured for the first time the low-mass end of the IMF from the integrated spectra of a Milky Way-like galaxy, NGC3351. We found that the slope ofAdvertised on
-
The transient Swift J1727.8-162 is the latest member of the X-ray binary black hole family to be discovered. They are formed by a black hole and a low-mass star whose gas is stripped off and accreted to the black hole via an accretion disc. The high temperature of the accretion disc makes it shine in all energy bands up to X-rays, and is particularly bright during epochs known as outbursts. In this novel study, published just a few months after the discovery of the system, we present 20 epochs of optical spectroscopy obtained with the GTC-10.4m telescope. The spectra cover the main accretionAdvertised on
-
Recent observational studies suggest that feedback from active galactic nuclei (AGNs)—the energetic centres powered by supermassive black holes—may play an important role in the formation and evolution of dwarf galaxies, contrary to the standard thought. We investigated this using two sets of 12 cosmological magnetohydrodynamic simulations of the formation of dwarf galaxies: one set using a version of the AURIGA galaxy formation physics model including AGN feedback and a parallel set with AGN feedback turned off. Our results reveal that AGNs can suppress the star formation (SF) of dwarfAdvertised on