Related papers: Evidence of Enhanced Ionization in Protostellar En…
It remains a key challenge to establish the molecular content of different components of low-mass protostars, like their envelopes and disks, and how this depends on the evolutionary stage and/or environment of the young stars. Observations…
The chemical evolution in star forming regions is driven by the interplay between gas and ice mantles. Identifying the ice compositions at the early stage of star formation thus provides constraints on the chemical processes inaccessible…
Characterizing the physical conditions (density, temperature, ionization state, metallicity, etc) of the interstellar medium is critical to our understanding of the formation and evolution of galaxies. Here we present a multi-line study of…
We performed SMA observations in the C18O (2-1) emission line toward six Class 0 and I protostars, to study rotational motions of their surrounding envelopes and circumstellar material on 100 to 1000 AU scales. C18O (2-1) emission with…
We study protostellar envelope and outflow evolution using Hubble Space Telescope NICMOS or WFC3 images of 304 protostars in the Orion Molecular clouds. These near-IR images resolve structures in the envelopes delineated by the scattered…
We calculate the ionisation fraction in protostellar disk models using a number of different chemical reaction networks, including gas-phase and gas-grain reaction schemes. The disk models we consider are conventional alpha-disks, which…
This paper presents a millimeter wavelength aperture-synthesis study of the spatial variations of the chemistry in the envelope around the deeply embedded low-mass protostar L483-mm on 1000 AU (5") scales. Lines of 8 molecular species…
We utilize medium-resolution JWST/NIRSpec observations of 164 galaxies at $z=2.0-9.3$ from the Cosmic Evolution Early Release Science (CEERS) survey to investigate the evolution of the excitation and ionization properties of galaxies at…
Recent high-resolution observations have enabled detailed investigations of the circumstellar environments around Class 0/I protostars. Several studies have reported that the infall velocity of the envelope is a few times smaller than the…
We present a detailed millimeter line study of the circumstellar environment of the low-luminosity Class 0 protostar IRAM 04191+1522 in the Taurus molecular cloud. New line observations demonstrate that the ~14000 AU radius protostellar…
Low-mass protostars are the extrasolar analogues of the natal Solar System. Sophisticated physicochemical models are used to simulate the formation of two protoplanetary discs from the initial prestellar phase, one dominated by viscous…
(English) In this lecture I discuss recent progress in the understanding of the chemical evolution of protoplanetary disks that resemble our Solar system during the first ten million years. At the verge of planet formation, strong…
Protostellar evolution, following the formation of the protostar is becoming reasonably well characterized, but the evolution from a prestellar core to a protostar is not well known, although the first hydrostatic core (FHSC) must be a…
The inner regions of the envelopes surrounding young protostars are characterised by a complex chemistry, with prebiotic molecules present on the scales where protoplanetary disks eventually may form. This paper introduces a systematic…
Ionization is important for magnetohydrodynamics and chemistry in protoplanetary disks but known ionization sources are often weak along the midplane. We present, for the first time, data from a laboratory experiment, where we measure ions…
Snowlines are key ingredients for planet formation. Providing observational constraints on the locations of the major snowlines is therefore crucial for fully connecting planet compositions to their formation mechanism. Unfortunately, the…
We have mapped at small spatial scales the temperature and the velocity field in the protocluster associated with IRAS 05345+3157, which contains both intermediate-/high-mass protostellar candidates and starless condensations, and is thus…
We use the POLARIS radiative transfer code to produce simulated circular polarization Zeeman emission maps of the CN $J = 1 - 0$ molecular line transition for two types of protostellar envelope magnetohydrodynamic simulations. Our first…
Recent observations of protostars with the James Webb Space Telescope have revealed unprecedented chemical complexity from their ice absorption features. However, these spectra are likely influenced by radiative transfer effects, and there…
Low dust opacity spectral indices ($\beta < 1$) measured in the inner envelopes of class 0/I young stellar objects (age $\sim 10^{4-5}$ yr) have been interpreted as the presence of (sub-)millimetre dust grains in these environments. The…