Related papers: Observations of L1521F: a highly evolved starless …
We present here findings for C18O depletion in eight starless cores in Taurus: TMC-2, L1498, L1512, L1489, L1517B, L1521E, L1495A-S, and L1544. We compare observations of the C18O J=2-1 transition taken with the ALMA prototype receiver on…
We have characterized the physical structure and chemical composition of two close-to-round starless cores in Taurus-Auriga, L1498 and L1517B. Our analysis is based on high angular resolution observations in at least two transitions of NH3,…
Using the IRAM 30m telescope, we mapped the methanol emission in the pre-stellar core L1544 and observed singly deuterated methanol (CH$_2$DOH and CH$_3$OD) towards the dust peak of L1544. Non-LTE radiative transfer modelling was performed…
Pre-stellar cores represent a critical evolutionary phase in low-mass star formation. We aim to unveil the detailed thermal structure and density distribution of three early-stage cores, starless core L1517B, and prestellar core L694-2 and…
Context. Low-mass star-forming cores differ from their surrounding molecular cloud in turbulence, shape, and density structure. Aims. We aim to understand how dense cores form out of the less dense cloud material by studying the connection…
Seven isolated, nearby low-mass starless molecular cloud cores have been observed as part of the Herschel key program Earliest Phases of Star formation (EPoS). By applying a ray-tracing technique to the obtained continuum emission and…
Recent observations of the pre-stellar core L1544 and the younger starless core L1498 have revealed that complex organic molecules (COMs) are enhanced in the gas phase toward their outer and intermediate-density shells. Our goal is to…
Molecular deuteration is commonly seen in starless cores and is expected to occur on a timescale comparable to that of the core contraction. Thus, the deuteration serves as a chemical clock, allowing us to investigate dynamical theories of…
Both analytic and numerical radiative transfer models applied to high spectral resolution CS and N2H+ data give insight into the evolutionary state of L1551 MC. This recently discovered pre-protostellar core in L1551 appears to be in the…
Observing and characterizing pre- and protostellar cores in the earliest and densest stages of star formation is challenging due to their short timescales and high densities, limiting the suitable tracers and targets. We conducted…
Prestellar cores represent the initial conditions of star formation, but heavy molecules such as CO are strongly depleted in their cold, dense interiors, limiting the ability to probe core centers. Deuterated molecular ions therefore emerge…
We report ALMA observations in 0.87 mm continuum and $^{12}$CO ($J$ = 3--2) toward a very low-luminosity ($<$0.1 $L_{\odot}$) protostar, which is deeply embedded in one of the densest core MC27/L1521F, in Taurus with an indication of…
The study of deuteration in pre-stellar cores is important to understand the physical and chemical initial conditions in the process of star formation. In particular, observations toward pre-stellar cores of methanol and deuterated…
Understanding the chemical processes during starless core and prestellar core evolution is an important step in understanding the initial stages of star and disk formation. This project is a study of deuterated ammonia, o-NH$_2$D, in the…
We have performed a pointed survey of N2D+ 2-1 and N2D+ 3-2 emission toward 64 N2H+-bright starless and protostellar cores in the Perseus molecular cloud using the Arizona Radio Observatory Submillimeter Telescope and Kitt Peak 12 m…
Understanding the initial conditions of star formation requires both observational studies and theoretical works taking into account the magnetic field, which plays an important role in star formation processes. Herein, we study the young…
The formation scenario of brown dwarfs is still unclear because observational studies to investigate its initial condition are quite limited. Our systematic survey of nearby low-mass star-forming regions using the Atacama Compact Array (aka…
We present new results on CO depletion in a sample of nearby pre-stellar cores, based on observations of the millimeter C17O and C18O lines and the 1.3 mm dust emission with the IRAM 30m telescope. In most cases, the distribution of CO is…
We present high spatial (<300 AU) and spectral (0.07 km/s) resolution Submillimeter Array observations of the dense starless cluster core Oph A-N6, in the 1 mm dust continuum and the 3-2 line of N2H+ and N2D+. The dust continuum…
L1521E seems unique among starless cores. It stands out in a distribution of a ratio (R) that we define to asses core evolution, and which compares the emission of the easily-depleted C18O molecule with that of the hard to deplete,…