Related papers: Heavy water stratification in a low-mass protostar
Aims: To investigate the chemical relations between complex organics based on their spatial distributions and excitation conditions in the low-mass young stellar objects IRAS 16293-2422 A and B. Methods: Interferometric observations with…
The chemical evolution in high-mass star-forming regions is still poorly constrained. Studying the evolution of deuterated molecules allows to differentiate between subsequent stages of high-mass star formation regions due to the strong…
We prepared a sample of oxirane doubly deuterated at one C atom and studied its rotational spectrum in the laboratory for the first time between 120~GHz and 1094~GHz. Accurate spectroscopic parameters up to eighth order were determined, and…
DK Cha is an intermediate-mass star in transition from an embedded configuration to a star plus disk stage. We aim to study the composition and energetics of the circumstellar material during this pivotal stage. Using the Range Scan mode of…
The millimeter-wave rotational emission lines (4(04)-3(03) and 5(05)-4(04)) of protonated carbon dioxide, HCO2+(HOCO+), has been detected toward the low-mass class 0 protostar IRAS 04368+2557 in L1527 with the IRAM 30 m telescope. This is…
We present a detailed model for the thermal balance, chemistry, and radiative transfer within quiescent dense molecular cloud cores that contain a central protostar. Large variations in the gas temperature are expected to affect the…
High angular resolution H2CO line observations have been carried out for the low mass proto-binary star IRAS 16293-2422 using the OVRO millimeter array. Simultaneous continuum observations reveal that the source most probably contains two…
Single-dish spectra and interferometric maps of (sub)mm lines of H2O-18 and HDO are used to study the chemistry of water in eight regions of high-mass star formation. The spectra indicate HDO excitation temperatures of ~110 K and column…
An accurate value of the deuterium/hydrogen (D/H) ratio in the local interstellar medium (LISM) and a better understanding of the D/H variations with position in the Galactic disk can provide essential information on the primordial D/H…
The Ultra Luminous InfraRed Galaxy Mrk 231 reveals up to seven rotational lines of water (H2O) in emission, including a very high-lying (E_{upper}=640 K) line detected at a 4sigma level, within the Herschel/SPIRE wavelength range, whereas…
Isocyanic acid (HNCO), the most stable of the simplest molecules containing the four main elements essential for organic chemistry, has been observed in several astrophysical environments such as molecular clouds, star-forming regions,…
We report on the detection of a rich water reservoir in the protostellar envelope of the Class 0 source HH211. In striking contrast to all other molecules detected with Herschel/PACS, water emission peaks around the central source where…
We report on the first far-IR detection of H2D+, using the Infrared Space Observatory, in the line of sight toward Sgr B2 in the galactic center. The transition at 126.853 um connecting the ground level of o-H2D+, 1_1,1 with the the 2_1,2…
Young massive stars are usually found embedded in dense and massive molecular clumps and are known for being highly obscured and distant. During their formation process, deuteration is regarded as a potentially good indicator of the…
We have observed the J=3-2 transition of N2H+ and N2D+ to investigate the trend of deuterium fractionation with evolutionary stage in three selected regions in the Infrared Dark Cloud (IRDC) G28.34+0.06 with the Submillimeter Telescope…
Recent observations of the HDO/H$_2$O ratio toward protostars in isolated and clustered environments show an apparent dichotomy, where isolated sources show higher D/H ratios than clustered counterparts. Establishing which physical and…
Water is one of the key molecules in the physical and chemical evolution of star- and planet-forming regions. We here report the first spatially resolved observation of thermal emission of (an isotopologue of) water with the Plateau de Bure…
Prestellar cores are unique laboratories for studies of the chemical and physical conditions preceding star formation. We observed the prestellar core L1544 in the fundamental transition of ortho-H2D+ (1_1,0-1_1,1) at different positions…
We present deep images of dust continuum emission at 450, 800, and 850 micron of the dark cloud LDN 1689N which harbors the low-mass young stellar objects (YSOs) IRAS 16293-2422A and B (I16293A and I16293B) and the cold prestellar object…
Aims. The purpose of this study is to examine the prediction that the deuterated H3+ ion, H2D+, can be found exclusively in the coldest regions of molecular cloud cores. This is also a feasibility study for the detection of the ground-state…