Chemistry and dynamics of pre- and proto-stellar cores – ChemoDyn
ChemoDyn: Understanding the chemical and dynamical evolution of pre- and proto-stellar cores
Pre- and proto-stellar cores represent the earliest stages of the formation of a star. This phases are crucial because they determine the initial composition of the proto-planetary disk. Much progress in our understanding of these objects have been done in past years, thanks (sub-) millimeter observations. However, most studies so far have used observations with resolutions of a few 10«, and the physical and chemical structure of these objects on smaller scales remains poorly known.
Using chemistry to understand star formation
The Chemodyn project aims at studying the physical and chemical properties of a large sample of Class 0 protostars. The main objectives of the project are 1) to develop a state-of-the-art chemo-dynamical of the evolution of pre- and proto-stellar core and 2) to compare the predictions of this model with interferometric observations at sub-arcsecond resolution. We aim at answering the following questions:<br /><br /><br />1. How the chemical abundances measured in Class 0 protostars compare to chemo-dynamical model predictions?<br /><br />2. How the chemical composition differs from one protostar to the other, and how it evolves?<br /><br />3. What is the origin of the grain mantle evaporation observed in the hot-corinos?<br /><br />4. What is the velocity profile in Class 0 protostellar envelopes, and how it compares with model predictions?<br /><br />5. Overall, what constraints can high angular resolution line observations place on star formation theories? For example, can lines be used as «chemical-clock« and in turn solve the long-standing controversy between the «fast« and “slow” star formation paradigms?
Our approach combines observations with a theoretical/modelling effort. Our observations are part of an extensive survey of the line and continuum emission from young protostars with the Plateau de Bure interferometer at sub-arcsecond resolution. Follow-up observations with ALMA and NOEMA will be carried-out. In order to interpret these observations, we are developping a new chemo-dynamical model combining the results of state-of-the art MHD simulations of core collapse with a complete chemistry network and a radiative transfer model. This will allow for a direct comparison between our observations and the predictions our model. This comparison is expected to bring important constraints on the formation and evolution of pre- and protostellar cores, and in turn on star formation theories.
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Pre- and protostellar cores represent the earliest stage of the formation of a star. This phases are crucial for the future evolution of the star, as its final mass and the initial composition of the proto-planetary disk that may eventually form planet will be determined during these phases. In the past years, much progress has been done in our understanding of the chemical structure of these objects, thanks to the dramatic increase of the sensitivity of millimiter and sub-millimeter ground based telescopes. In fact, it is now possible to use chemistry as a tool to constrain both physical and chemical characteristics of these objects. However, most studies so far have used single dish observations with typical resolutions of a few tens of arc seconds, and the physical and chemical structures if cores on smaller scales remains poorly know. Here we propose to carry-out a study the physical and chemical properties of a large sample of Class 0 protostars, using both an observational and theorical/modelling approach. Our observations are part of an extensive survey of the line and continuum emission from young protostars with the Plateau de Bure interferometer at sub-arcsecond resolution. Follow-up observations with ALMA and NOEMA will be carried-out. We propose to develop a new chemo-dynamical model combining the results of state-of-the art MHD simulations of core collapse with a complete chemistry network and a radiative transfer model. The direct comparison between sub-arcsecond resolution observations and the predictions our chemo-dynamical model is expected to bring important constraints on the formation and evolution of pre- and protostellar cores, and in turn on star formation theories.
Project coordination
Sébastien MARET (Institut de Planétologie et d'Astrophysique de Grenoble) – sebastien.maret@obs.ujf-grenoble.fr
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
Partner
IPAG Institut de Planétologie et d'Astrophysique de Grenoble
Help of the ANR 243,415 euros
Beginning and duration of the scientific project:
December 2012
- 36 Months
