Related papers: A lambda 3mm and 1mm line survey toward the yellow…
Aims: Little information exists on the circumstellar molecular abundance stratifications of many molecules. The aim is to study the circumstellar chemical abundance pattern of 11 molecules and isotopologs ($^{12}$CO, $^{13}$CO, SiS,…
We obtained near-infrared long-baseline interferometry of IRC+10420 with the AMBER instrument of ESO's Very Large Telescope Interferometer (VLTI) in low and high spectral resolution (HR) mode to probe the photosphere and the innermost…
IRC +10420 and AFGL 2343 are the unique, known yellow hypergiants (YHGs) presenting a heavy circumstellar envelope (CSE). We aim to study the morphology, exceptional kinematics, and excitation conditions of their CSEs, and the implications…
We present an unbiased molecular line survey toward the carbon-rich circumstellar envelope CIT 6 carried out between 90 and 116 GHz with the Arizona Radio Observatory 12 m telescope. A total of 42 lines assigned to 10 molecular species and…
The study of complex nitrogen (N)-bearing molecules is essential for probing the physical and chemical evolution of star-forming regions. In this paper, we present the identification of rotational emission lines from several complex…
A new chemical model is presented for the carbon-rich circumstellar envelope of the AGB star IRC+10216. The model includes shells of matter with densities that are enhanced relative to the surrounding circumstellar medium. The chemical…
We have studied 14 southern infrared dark clouds (IRDCs) using the data taken from the Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey and the GLIMPSE and MIPSGAL mid-infrared survey of the inner Galaxy. The physical and chemical…
We study the chemical complexity towards the central parts of the starburst galaxy M82, and investigate the role of certain molecules as tracers of the physical processes in the galaxy circumnuclear region. We carried out a spectral line…
The circumstellar envelopes of carbon-rich AGB stars show a chemical complexity that is exemplified by the prototypical object IRC +10216, in which about 60 different molecules have been detected to date. Most of these species are carbon…
To understand the evolutionary stage of the peculiar supergiant IRC+10420, we have been taking spectra for several years at the 6m telescope. The optical spectrum of IRC+10420 of the years from 1992 through 1996 points to the increase in…
Aims. The comparative study of several molecular species at the origin of the gas phase chemistry in the diffuse interstellar medium (ISM) is a key input in unraveling the coupled chemical and dynamical evolution of the ISM. Methods. The…
We present 2 - 5 micron adaptive optics (AO) imaging and polarimetry of the famous hypergiant stars IRC +10420 and VY Canis Majoris. The imaging polarimetry of IRC +10420 with MMT-Pol at 2.2 micron resolves nebular emission with intrinsic…
AGB stars are major contributors to the chemical enrichment of the ISM through nucleosynthesis and extensive mass loss. Most of our current knowledge of AGB atmospheric and circumstellar chemistry, in particular in a C-rich environment, is…
Aims: Our aim is to identify the dominant molecular cooling lines and characteristic emission features in the 1.3 mm window of distinct regions in the northern part of the Orion A molecular cloud. By defining and analysing template regions,…
Context. The earliest phases of high-mass star formation are poorly understood. Aims. Our goal is to determine the physical conditions and kinematic structure of massive star-forming cloud clumps. Methods. We analyze H$_2$O 557 GHz line…
A spectral line survey of IRC +10216 between 13.3 and 18.5 GHz is carried out using the Shanghai Tian Ma 65 m Radio Telescope (TMRT-65m) with a sensitivity of < 7 mK. Thirty-five spectral lines of 12 different molecules and radicals are…
We report on the discovery of strong intensity variations in the high rotational lines of abundant molecular species towards the archetypical circumstellar envelope of IRC+10216. The observations have been carried out with the HIFI…
In recent years, many questions have arisen regarding the chemistry of photochemical products in the carbon-rich winds of evolved stars. To address them, it is imperative to constrain the distributions of such species through high angular…
We present a spectral line survey of the C-rich envelope CIT 6 in the 2mm and 1.3mm bands carried out with the Arizona Radio Observatory (ARO) 12m telescope and the Heinrich Hertz Submillimeter Telescope (SMT). The observations cover the…
The observation of oxygen (O)- and nitrogen (N)-bearing molecules gives an idea about the complex prebiotic chemistry in the interstellar medium (ISM). In this article, we present the identification of the rotational emission lines of…