| Description |
We propose a search for far-infrared features from polycyclic aromatic hydrocarbon molecules (PAHs) in a small sample of protoplanetary disks around late-type T Tau stars. These objects were identified in the course of our large Spitzer-IRS survey of the Orion A cloud to have mid-infrared PAH features with unusual profiles, which are far too bright to explain by photoexcitation by their host stars; they must be excited by ultraviolet light from their more massive neighbors. Recent laboratory spectra of PAHs demonstrate the variation of wavelength and strength with molecule size for the far-infrared features of PAHs, a sensitivity that is lacking in the mid-infrared features. The observation of such features in disks around low-mass stars, in which we frequently see the effects of coagulation and growth among the silicate-grain population, represents an opportunity to search for size variation among the PAH population, a congruence with the PAH molecules found in the primitive meteorites, and perhaps hints of the role played by carbonaceous molecules in the assembly of solid bodies in disks. |
| Keywords |
Herschel Space Observatory data, ESA Herschel mission dataset, far-infrared astronomy observations, submillimeter astronomy data, infrared space telescope observations, PACS photometer data, PACS spectrometer data, SPIRE photometer data, SPIRE Fourier transform spectrometer data, HIFI heterodyne spectroscopy data, far-infrared spectroscopy dataset, submillimeter spectral line observations, cold universe observations dataset, star formation infrared data, molecular cloud far-infrared observations, interstellar medium spectroscopy data, protoplanetary disk infrared observations, galaxy evolution far-infrared data, dust emission submillimeter observations, cosmic infrared background measurements, extragalactic infrared survey data, calibrated level 2 data products, FITS files astronomy, spectral cubes far-infrared, flux-calibrated maps, continuum photometry data, spectral energy distribution measurements, ESA Herschel Science Archive data |
