Herschel-SPIRE FTS spectroscopy of the carbon-rich objects AFGL 2688, AFGL 618 and NGC 7027

Abstract

We present far-infrared and submillimetre spectra of three carbon-rich evolved objects, AFGL 2688, AFGL 618 and NGC 7027. The spectra were obtained with the SPIRE Fourier transform spectrometer on board the Herschel Space Observatory, and cover wavelengths from 195-670 um, a region of the electromagnetic spectrum hitherto difficult to study in detail. The far infrared spectra of these objects are rich and complex, and we measure over 150 lines in each object. Lines due to 18 different species are detected. We determine physical conditions from observations of the rotational lines of several molecules, and present initial large velocity gradient models for AFGL 618. We detect water in AFGL 2688 for the first time, and confirm its presence in AFGL 618 in both ortho and para forms. In addition, we report the detection of the J=1-0 line of CH+ in NGC 7027.

Accepted for A&A Herschel special issue. 4 tables, 2 figures.

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• Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy
• The Herschel-SPIRE instrument and its in-flight performance
• In-flight calibration of the Herschel-SPIRE instrument
• Planetary Nebulae: Observational Properties, Mimics, and Diagnostics
• The chemistry of vibrationally excited H2 in the interstellar medium
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Cited by in corpus (20)

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• First detection of the Methylidyne cation (CH+) fundamental rotational line with the Herschel/SPIRE FTS
• Through the magnifying glass: ALMA acute viewing of the intricate nebular architecture of OH231.8+4.2
• Herschel SPIRE and PACS observations of the red supergiant VY CMa: analysis of the molecular line spectra
• Systematic characterisation of the Herschel SPIRE Fourier Transform Spectrometer
• Herschel Planetary Nebula Survey (HerPlaNS) - First Detection of OH+ in Planetary Nebulae
• Modeling the physical and excitation conditions of the molecular envelope of NGC 7027
• A Molecular Line Survey of the Carbon-Rich Proto-Planetary Nebula AFGL 2688 in the 3mm and 1.3mm Windows
• PDRs4All XI. Detection of infrared CH${}^{+}$ and CH${}_3^{+}$ rovibrational emission in the Orion Bar and disk d203-506: evidence of chemical pumping
• Mapping the Central Region of the PPN CRL 618 at Sub-arcsecond Resolution at 350 GHz
• Observations and analysis of CH${}^{+}$ vibrational emissions from the young, carbon-rich planetary nebula NGC 7027: a textbook example of chemical pumping
• Herschel Planetary Nebula Survey (HerPlaNS): Hydrogen Recombination Laser Lines in Mz 3
• The Chemical composition of the post-AGB F-supergiant CRL 2688
• Charting Circumstellar Chemistry of Carbon-rich AGB Stars: I. ALMA 3 mm spectral surveys
• Warm CO in evolved stars from the THROES catalogue. II. Herschel/PACS spectroscopy of C-rich envelopes
• Astronomical imaging Fourier spectroscopy at far-infrared wavelengths
• Detection of the [C I] $\lambda$8727 emission line. Low-ionization structures in NGC 7009