Related papers: L1521E: A Starless Core in the Early Evolutionary …
Aims: Our goal is to set constraints on the evolutionary state of the dense core Cha-MMS1 in the Chamaeleon I molecular cloud. Methods: We analyze molecular line observations carried out with the new submillimeter telescope APEX. We look…
Spectral line profiles of several molecules observed towards the pre-stellar core L1544 appear double-peaked. For abundant molecular species this line morphology has been linked to self-absorption. However, the physical process behind the…
We have mapped the starless core TMC-1C in a variety of molecular lines with the IRAM 30m telescope. High density tracers show clear signs of self-absorption and sub-sonic infall asymmetries are present in N2H+ (1-0) and DCO+ (2-1) lines.…
Dense low mass cores in nearby clouds like Taurus and Auriga are some of the simplest sites currently forming stars like our Sun. Because of their simplicity and proximity, dense cores offer the clearest view of the different phases of star…
Towards the pre-stellar core L1544, the methanol (CH$_3$OH) emission forms an asymmetric ring around the core centre, where CH$_3$OH is mostly in solid form, with a clear peak 4000~au to the north-east of the dust continuum peak. As part of…
We have carried out observations of CCH and its two $^{13}$C isotopologues, $^{13}$CCH and C$^{13}$CH, in the 84 - 88 GHz band toward two starless cores, L1521B and L134N (L183), using the Nobeyama 45 m radio telescope. We have detected…
Starless cores represent the initial stage of evolution toward (proto)star formation, and a subset of them, known as prestellar cores, with high density (~ 10^6 cm^-3 or higher) and being centrally concentrated are expected to be embryos of…
Protostellar cores located near supernova remnants are considered potential analogues of the birth environment of the solar system. However, the extent to which supernovae influence their chemical evolution remains unclear. We report the…
We have mapped the dense dark core L1544 in H13CO+(1-0), DCO+(2-1), DCO+(3-2), N2H+(1-0), NTH+(3-2), N2D+(2-1), N2D+(3-2), C18O(1-0), and C17O(1-0) using the IRAM 30-m telescope. We have obtained supplementary observations of HC18O+(1-0),…
Determining the structure of and the velocity field in prestellar cores is essential to understanding protostellar evolution.} {We have observed the dense prestellar cores L 1544 and L 183 in the $N = 1 \to 0$ rotational transition of CN…
Young stars form in molecular cores, which are dense condensations within molecular clouds. We have searched for molecular cores traced by $^{13}$CO $J=1\to 0$ emission in the Taurus molecular cloud and studied their properties. Our data…
High resolution molecular line observations of CS, HCO+, C18O and N2H+ were obtained toward the starless globule FeSt 1-457 in order to investigate its kinematics and chemistry. The HCO+ and CS spectra show clear self-reversed and…
Abridged: The thermal structure of a starless core is crucial for our understanding of the physics in these objects and hence for our understanding of star formation. Theory predicts a gas temperature drop in the inner 5000 AU of these…
We searched for shocked carbon chain chemistry (SCCC) sources with C$_3$S abundances surpassing those of HC$_5$N towards the dark cloud L1251, using the Effelsberg telescope at K-band (18 -- 26\,GHz). L1251-1 and L1251-3 are identified as…
We present molecular line observations of L1251B, a small group of pre- and protostellar objects, and its immediate environment in the dense C18O core L1251E. These data are complementary to near-infrared, submillimeter and millimeter…
We combine dynamical and non-equilibrium chemical modeling of evolving prestellar molecular cloud cores, and explore the evolution of molecular abundances in the contracting core. We model both magnetic cores, with varying degrees of…
We present the results of a single-pointing survey of 207 dense cores embedded in Planck Galactic Cold Clumps distributed in five different environments ($\lambda$ Orionis, Orion A, B, Galactic plane, and high latitudes) to identify dense…
The deuterium fractionation in starless cores gives us a clue to estimate their lifetime scales, thus allowing us to distinguish between different dynamical theories of core formation. Cores also seem to be subject to a differential N2 and…
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 study the kinematics of the dense gas of starless and protostellar cores traced by the N2D+(2-1), N2H+(1-0), DCO+(2-1), and H13CO+(1-0) transitions along the L1495 filament and the kinematic links between the cores and the surrounding…