Search Publications
Luminosities and mass-loss rates of Local Group AGB stars and red supergiants
Groenewegen, M. A. T.; Sloan, G. C.
Context. Mass loss is one of the fundamental properties of asymptotic giant branch (AGB) stars, and through the enrichment of the interstellar medium, AGB stars are key players in the life cycle of dust and gas in the universe. However, a quantitative understanding of the mass-loss process is still largely lacking.
Aims: We aim to investigate…
Infrared spectra of complex organic molecules in astronomically relevant ice matrices. I. Acetaldehyde, ethanol, and dimethyl ether
van Dishoeck, E. F.; Boogert, A. C. A.; Linnartz, H. +2 more
Context. The number of identified complex organic molecules (COMs) in inter- and circumstellar gas-phase environments is steadily increasing. Recent laboratory studies show that many such species form on icy dust grains. At present only smaller molecular species have been directly identified in space in the solid state. Accurate spectroscopic labo…
Chemical content of the circumstellar envelope of the oxygen-rich AGB star R Doradus. Non-LTE abundance analysis of CO, SiO, and HCN
de Koter, A.; Decin, L.; Wyrowski, F. +5 more
Context. The stellar outflows of low- to intermediate-mass stars are characterised by a rich chemistry. Condensation of molecular gas species into dust grains is a key component in a chain of physical processes that leads to the onset of a stellar wind. In order to improve our understanding of the coupling between the micro-scale chemistry and mac…
Abundance of SiC2 in carbon star envelopes
Alcolea, J.; Cernicharo, J.; Goicoechea, J. R. +6 more
Context. Silicon carbide dust is ubiquitous in circumstellar envelopes around C-rich asymptotic giant branch (AGB) stars. However, the main gas-phase precursors leading to the formation of SiC dust have not yet been identified. The most obvious candidates among the molecules containing an Si-C bond detected in C-rich AGB stars are SiC2,…
Constraining physical conditions for the PDR of Trumpler 14 in the Carina Nebula
Onaka, Takashi; Okada, Yoko; Le Petit, Franck +5 more
We investigate the physical conditions of the CO gas, based on the submillimeter imaging spectroscopy from a 2' × 7' (1.5 × 5 pc2) area near the young star cluster, Trumpler 14 of the Carina Nebula. The observations presented in this work are taken with the Fourier Transform Spectrometer (FTS) of the Spectral and Photometric Imaging REc…
Near-infrared spectroscopic observations of massive young stellar object candidates in the central molecular zone
Schultheis, M.; Ryde, N.; Rojas-Arriagada, A. +6 more
Context. The central molecular zone (CMZ) is a 200 pc region around the Galactic centre. The study of star formation in the central part of the Milky Way is of great interest as it provides a template for the closest galactic nuclei.
Aims: We present a spectroscopic follow-up of photometrically selected young stellar object (YSO) candidates i…
Circumstellar ammonia in oxygen-rich evolved stars
Menten, K. M.; Greathouse, T. K.; Wyrowski, F. +3 more
Context. The circumstellar ammonia (NH3) chemistry in evolved stars is poorly understood. Previous observations and modelling showed that NH3 abundance in oxygen-rich stars is several orders of magnitude above that predicted by equilibrium chemistry.
Aims: We would like to characterise the spatial distribution and excita…
Modeling dust emission in PN IC 418
Morisset, C.; García-Lario, P.; Szczerba, R. +2 more
We investigated the infrared (IR) dust emission from PN IC 418, using a detailed model controlled by a previous determination of the stellar properties and the characteristics of the photoionized nebula, keeping as free parameters the dust types, amounts, and distributions relative to the distance of the central star. The model includes the ionize…
C+ distribution around S 1 in ρ Ophiuchi
Güsten, R.; Mookerjea, B.; Sandell, G. +2 more
We analyze a [C II] 158 µm map obtained with the L2 GREAT receiver on SOFIA of the reflection nebula illuminated by the early B star S 1 in the ρ Oph A cloud core. This data set has been complemented with maps of CO(3-2), 13CO(3-2), and C18O(3-2), observed as a part of the James Clerk Maxwell Telescope (JCMT) Gould Belt…
The spatial extent of polycyclic aromatic hydrocarbons emission in the Herbig star HD 179218
Rebolo, R.; Wolf, S.; Taha, A. S. +7 more
Aim. We investigate, in the mid-infrared, the spatial properties of the polycyclic aromatic hydrocarbons (PAHs) emission in the disk of HD 179218, an intermediate-mass Herbig star at 300 pc.
Methods: We obtained mid-infrared images in the PAH-1, PAH-2 and Si-6 filters centered at 8.6, 11.3, and 12.5 µm, and N-band low-resolution spectra…