Atypical dust species in the ejecta of classical novae

L. A. Helton, A. Evans, C. E. Woodward, R. D. Gehrz

Research output: Chapter in Book/Report/Conference proceedingConference contribution

20 Scopus citations


A classical nova outburst arises from a thermonuclear runaway in the hydrogen-rich material accreted onto the surface of a white dwarf in a binary system. These explosions can produce copious amounts of heavy element enriched material that are ejected violently into the surrounding interstellar medium. In some novae, conditions in the ejecta are suitable for the formation of dust of various compositions, including silicates, amorphous carbon, silicon carbide, and hydrocarbons. Multiple dust grain types are sometimes produced in the same system. CO formation in novae may not reach saturation, thus invalidating the usual paradigm in which the C:O ratio determines the dust species. A few novae, such as V705 Cas and DZ Cru, have exhibited emission features near 6, 8, and 11 μmthat are similar to "Unidentified Infrared" (UIR) features, but with significant differences in position and band structure. Here, we present Spitzer IRS spectra of two recent dusty novae, V2361 Cyg and V2362 Cyg, that harbor similar peculiar emission structures superimposed on features arising from carbonaceous grains. In other astronomical objects, such as star forming regions and young stellar objects, emission peaks at 6.2, 7.7, and 11.3 μmhave been associated with polycyclic aromatic hydrocarbon (PAH) complexes. We suggest that hydrogenated amorphous carbon (HAC) may be the source of these features in novae based upon the spectral behavior of the emission features and the conditions under which the dust formed.

Original languageEnglish (US)
Title of host publicationPAHs and the Universe
Subtitle of host publicationA Symposium to Celebrate the 25th Anniversary of the PAH Hypothesis
Number of pages6
StatePublished - 2011
EventPAHs and the Universe: A Symposium to Celebrate the 25th Anniversary of the PAH Hypothesis - Toulouse, France
Duration: May 31 2010Jun 4 2010

Publication series

NameEAS Publications Series
ISSN (Print)1633-4760
ISSN (Electronic)1638-1963


OtherPAHs and the Universe: A Symposium to Celebrate the 25th Anniversary of the PAH Hypothesis


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