相关论文: Molecular Abundances in B68

The cosmological origin of carbon, the fourth most abundant element in the Universe, is not well known and matter of heavy debate. We investigate the behavior of C/O to O/H in order to constrain the production mechanism of carbon. We…

We derive the Mg/H ratio in the Orion nebula and in 30 Doradus. We also derive the O/H and the Fe/O ratios in the extremely metal poor galaxy SBS 0335-052. We estimate the dust depletions of Mg, Si, and Fe in Galactic and extragalactic H II…

Chemical diversity of low-mass protostellar sources has so far been recognized, and environmental effects are invoked as its origin. In this context, observations of isolated protostellar sources without influences of nearby objects are of…

We use the IRAM Large Program EMPIRE and new high-resolution ALMA data to measure 13CO(1-0)/C18O(1-0) intensity ratios across nine nearby spiral galaxies. These isotopologues of CO are typically optically thin across most of the area in…

We used the Plateau de Bure Interferometer to search for $\lambda$3mm absorption lines of HOC+ from local diffuse and translucent clouds occulting compact extragalactic mm-wave continuum sources. We detected HOC+ in three directions with…

The ``integral-shaped filament'' of the Orion A giant molecular cloud was mapped in N2H+, and its northern end, the OMC-2/3 region was observed also in HC3N and CCS. The N2H+ distribution is similar to the dust continuum distribution,…

The aim of this study is to investigate systematic chemical differentiation of molecules in regions of high mass star formation. We observed five prominent sites of high mass star formation in HCN, HNC, HCO+, their isotopes, C18O, C34S and…

C$_4$H and $c$-C$_3$H$_2$, as unsaturated hydrocarbon molecules, are important for forming large organic molecules in the interstellar medium. We present mapping observations of C$_4$H ($N$=9$-8$) lines, $c$-C$_3$H$_2$…

Complex organic molecules (COMs) have been observed towards several low-mass young stellar objects (LYSOs). Small and heterogeneous samples have so far precluded conclusions on typical COM abundances, as well as the origin(s) of abundance…

CNO abundances in galaxies bear on issues of galactic evolution as well as stellar evolution and nucleosynthesis. Knowledge about them in dwarf and spiral galaxies depends mainly on emission lines from H II regions, with information from…

Infrared Dark Clouds are expected to harbor sources in different, very young evolutionary stages. To better characterize these differences, we observed a sample of 43 massive Infrared Dark Clouds, originally selected as candidate high-mass…

We present fully sampled ^{12}$CO, ^{13}CO J=2-1, 3-2 maps of the inner $\sim 1'\times 1'$ region of NGC 1068. We combine these measurements with an existing interferometric map of ^{12}CO J=1-0 that includes single dish data and thus…

%methods {We used the EMIR receiver and FTS spectrometer at the IRAM 30m to construct absorption spectra toward bright extra-galactic background sources at 195 kHz spectral resolution ($\approx$ 0.6 \kms). We used the IRAM Plateau de Bure…

We report the detection of more than 48 velocity-resolved ground rotational state transitions of H2(16)O, H2(18)O, and H2(17)O - most for the first time - in both emission and absorption toward Orion KL using Herschel/HIFI. We show that a…

This paper is the third in a series reporting on a study of carbon abundances in a carefully chosen sample of planetary nebulae representing a large range in progenitor mass and metallicity. We make use of the IUE Final Archive database…

We discuss the accuracy of the abundance determinations of H II regions in our Galaxy and other galaxies. We focus on the main observational constraints derived from abundance determinations that have implications for models of galactic…

Molecular hydrogen (H$_2$) is by far the most abundant molecule in the Universe. However, due to the low emissivity of H$_2$, carbon monoxide (CO) is widely used instead to trace molecular gas in galaxies. The relative abundances of these…

There is a robust polyatomic chemistry in diffuse, partially-molecular interstellar gas that is readily accessible in absorption at radio/mm/sub-mm wavelengths. Accurate column densities are derived owing to the weak internal excitation, so…

(abridged) Our aim is to determine the radial abundance profile of SiO and HCN throughout the stellar outflow of R Dor, an oxygen-rich AGB star with a low mass-loss rate. We have analysed molecular transitions of CO, SiO, and HCN measured…

The chemical inventory of planets is determined by the physical and chemical processes that govern the early phases of star formation. The aim is to investigate N-bearing complex organic molecules towards two Class 0 protostars (B1-c and…