Search Publications
New light on Galactic post-asymptotic giant branch stars - I. First distance catalogue
Parker, Quentin A.; Vickers, Shane B.; Frew, David J. +1 more
We have commenced a detailed analysis of the known sample of Galactic post-asymptotic giant branch (PAGB) objects compiled in the Toruń catalogue of Szczerba et al., and present, for the first time, homogeneously derived distance determinations for the 209 likely and 87 possible catalogued PAGB stars from that compilation. Knowing distances are es…
Resolving structure of the disc around HD100546 at 7 mm with ATCA
Wilner, D. J.; van Dishoeck, E. F.; Pinilla, P. +7 more
There is much evidence that planet formation is occurring in the disc around the Herbig Be star HD100546. To learn more about the processes occurring in this disc, we conducted high-resolution imaging at 43/45 GHz with the Australia Telescope Compact Array. Multiple array configurations were used, providing a best spatial resolution of ∼0.15 arcse…
Spectroscopic constraints on CH3OH formation: CO mixed with CH3OH ices towards young stellar objects
Pontoppidan, K. M.; Blake, G. A.; Boogert, A. C. A. +3 more
The prominent infrared absorption band of solid CO - commonly observed towards young stellar objects (YSOs) - consists of three empirically determined components. The broad `red component' (2136 cm-1, 4.681 µm) is generally attributed to solid CO mixed in a hydrogen-bonded environment. Usually, CO embedded in the abundantly presen…
The 11.2 µm emission of PAHs in astrophysical objects
Sarre, P. J.; Candian, A.
The 11.2-µm emission band belongs to the family of the `unidentified' infrared emission bands seen in many astronomical environments. In this work, we present a theoretical interpretation of the band characteristics and profile variation for a number of astrophysical sources in which the carriers are subject to a range of physical conditions…
The abundance of 28Si32S, 29Si32S, 28Si34S, and 30Si32S in the inner layers of the envelope of IRC+10216
Cernicharo, J.; Fonfría, J. P.; Richter, M. J. +3 more
We present high spectral resolution mid-IR observations of SiS towards the C-rich AGB star IRC+10216 carried out with the Texas Echelon-cross-Echelle Spectrograph mounted on the NASA Infrared Telescope Facility. We have identified 204 ro-vibrational lines of 28Si32S, 26 of 29Si32S, 20 of 28Si<…
A Spitzer/IRAC characterization of Galactic AGB and RSG stars
Fazio, Giovanni G.; Reiter, Megan; Marengo, Massimo +1 more
We present new Spitzer/InfraRed Array Camera (IRAC) observations of 55 dusty long-period variables (48 asymptotic giant branch, AGB, and 6 red supergiant stars) in the Galaxy that have different chemistry, variability type, and mass-loss rate. O-rich AGB stars (including intrinsic S-type) tend to have redder [3.6]-[8.0] colours than carbon stars f…
Sulphur-bearing species in molecular clouds
Bilalbegović, G.; Baranović, G.
We study several molecules that could help in the solution of the missing sulphur problem in dense clouds and circumstellar regions, as well as in the clarification of the sulphur chemistry in comets. These sulphur molecules are the trimer (CH2S)3 and the tetramer (CH2S)4 of thioformaldehyde, pentathian …
Mid-infrared spectroscopy of the Andromeda galaxy
Barmby, P.; Smith, D. A.; Fazio, G. G. +6 more
We present Spitzer/Infrared Spectrograph (IRS) 5-21 µm spectroscopic maps towards 12 regions in the Andromeda galaxy (M31). These regions include the nucleus, bulge, an active region in the star-forming ring and nine other regions chosen to cover a range of mid-to-far-infrared colours. In line with previous results, polycyclic aromatic hydro…
Echelle spectroscopy and photoionization modelling of the entire planetary nebula NGC 6210
Dufour, R. J.; Bohigas, J.; Rodríguez, M. +1 more
High-resolution spectroscopy of NGC 6210, show that recombination line abundances of O+2 and Ne+2 are two to three times larger than forbidden line abundances, Te(O+2) is smaller than Te(N+) and possibly Te(S+), the ionized mass is ≃0.07 M⊙ and the p…
Mid-infrared variations of R Coronae Borealis stars
Rao, N. Kameswara; Lambert, David L.
Mid-infrared (IR) photometry of R Coronae Borealis stars obtained from various satellites from Infrared Astronomical Satellite (IRAS) to Wide-field Infrared Survey Explorer (WISE) has been utilized in studying the variations of the circumstellar dust's contributions to the spectral energy distribution of these stars. The variation of the fractiona…