English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We present medium-resolution 3 um spectroscopy of the carbon-richproto-planetary nebula IRAS 22272+5435. Spectroscopy with the Subaru Telescopeadaptive optics system revealed a spatial variation of hydrocarbon moleculesand dust surrounding the star. The ro-vibrational bands of acetylene (C2H2) andhydrogen cyanide (HCN) at 3.0 um are evident in the central star spectra. Themolecules are concentrated in the compact region near the center. The 3.3 and3.4 um emission of aromatic and aliphatic hydrocarbons is detected at 600--1300AU from the central star. The separation of spatial distribution between gasand dust suggests that the small hydrocarbon molecules are indeed the source ofsolid material, and that the gas leftover from the grain formation is beingobserved near the central star. The intensity of aliphatic hydrocarbon emissionrelative to the aromatic hydrocarbon emission decreases with distance from thecentral star. The spectral variation is well matched to that of a laboratoryanalog thermally annealed with different temperatures. We suggest that eitherthe thermal process after the formation of a grain or the variation in thetemperature in the dust-forming region over time determines the chemicalcomposition of the hydrocarbon dust around the proto-planetary nebula.Comment: 14 pages, 7 figures, Accepted for publication in the Astrophyical  Journa

Spatially Resolved 3 Micron Spectroscopy of IRAS 22272+5435: Formation and Evolution of Aliphatic Hydrocarbon Dust in Proto–Planetary Nebulae