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J/A+A/598/A116      A grid of 1D low-mass star formation models  (Vaytet+, 2017)

A grid of one-dimensional low-mass star formation collapse models. Vaytet N., Haugbolle T. <Astron. Astrophys. 598, A116 (2017)> =2017A&A...598A.116V (SIMBAD/NED BibCode)
ADC_Keywords: Models ; Protostars ; YSOs Keywords: stars: formation - stars: protostars - stars: low-mass - hydrodynamics - radiative transfer - gravitation Abstract: Numerical simulations of star formation are becoming ever more sophisticated, incorporating new physical processes in increasingly realistic set-ups. These models are being compared to the latest observations through state-of-the-art synthetic renderings that trace the different chemical species present in the protostellar systems. The chemical evolution of the interstellar and protostellar matter is very topical, with more and more chemical databases and reaction solvers available online to the community. The current study was developed to provide a database of relatively simple numerical simulations of protostellar collapse as a template library for observations of cores and very young protostars, and for researchers who wish to test their chemical modelling under dynamic astrophysical conditions. It was also designed to identify statistical trends that may appear when running many models of the formation of low-mass stars by varying the initial conditions. A large set of 143 calculations of the gravitational collapse of an isolated sphere of gas with uniform temperature and a Bonnor-Ebert-like density profile was undertaken using a 1D fully implicit Lagrangian radiation hydrodynamics code. The parameter space covered initial masses from 0.2 to 8M, temperatures of 5-30K, and radii 3000-30,000AU. A spread due to differing initial conditions and optical depths, was found in the thermal evolutionary tracks of the runs. Within less than an order of magnitude, all first and second Larson cores had masses and radii essentially independent of the initial conditions. Radial profiles of the gas density, velocity, and temperature were found to vary much more outside of the first core than inside. The time elapsed between the formation of the first and second cores was found to strongly depend on the first core mass accretion rate, and no first core in our grid of models lived for longer than 2000 years before the onset of the second collapse. The end product of a protostellar cloud collapse, the second Larson core, is at birth a canonical object with a mass and radius of about 3Mjup and 8Rjup, independent of its initial conditions. The evolution sequence which brings the gas to stellar densities can, however, proceed in a variety of scenarios, on different timescales or along different isentropes, but each story line can largely be predicted by the initial conditions. Description: We ran 143 1D simulations of gravitationally collapsing Bonnor-Ebert spheres, varying the initial mass, radius and temperature of the parent cloud. The properties of the first and second Larson cores are reported. The simulation outputs for each run are provided (one separate file per snapshot), as well as the initial parameters and core properties in a summary tablec1.dat. All the data from the simulations (figures and raw data for every output) are publicly available at this address: http://starformation.hpc.ku.dk/grid-of-protostars. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file tablec1.dat 279 143 Initial parameters and Larson core properties runs/* 0 143 *Individual simulation outputs
Note on runs/*: Each run directory has 1.3-1.6G size.
See also: http://starformation.hpc.ku.dk/grid-of-protostars : All data Byte-by-byte Description of file: tablec1.dat
Bytes Format Units Label Explanations
1- 6 A6 --- Run Run number 9- 19 E11.5 Msun M0 Initial cloud mass 22- 32 E11.5 K T0 Initial cloud temperature 35- 45 E11.5 AU R0 Initial cloud radius 48- 58 E11.5 g/cm3 rhoc Initial cloud central gas density 61- 71 E11.5 --- eps Ratio of Bonnor-Ebert mass to initial cloud mass 74- 84 E11.5 kyr tff1 Free-fall time computed from central density 87- 97 E11.5 kyr tff2 Free-fall time computed from average density 100-110 E11.5 kyr tff3 Modified free-fall time 113-123 E11.5 kyr tsound Cloud sound crossing time 126-136 E11.5 AU R1 First Larson core radius 139-149 E11.5 Msun M1 First Larson core mass 152-162 E11.5 Msun/yr Mdot1 First Larson core mass accretion rate 165-175 E11.5 Lsun Lacc1 First Larson core accretion luminosity 178-188 E11.5 Lsun Lrad1 First Larson core radiative luminosity 191-201 E11.5 yr taufc First Larson core lifetime 204-214 E11.5 AU R2 Second Larson core radius 217-227 E11.5 Msun M2 Second Larson core mass 230-240 E11.5 Msun/yr Mdot2 Second Larson core mass accretion rate 243-253 E11.5 Lsun Lacc2 Second Larson core accretion luminosity 256-266 E11.5 Lsun Lrad2 Second Larson core radiative luminosity 269-279 E11.5 Lsun Lout Luminosity at the grid outer edge
Description of files in runs/run* subdirectories: (Byte-by-byte Description of file: runs/run*/*) -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 20 E20.14 cm rc Cell central radius 23- 42 E20.14 cm ri Cell inner radius 44 A1 --- u- Gas velocity sign 45- 64 E20.14 cm/s u Gas velocity 67- 86 E20.14 10-7W/cm3 e Gas internal energy density (erg/cm3) 89-108 E20.14 10-7W/cm3 Er Radiative energy density (erg/cm3) 110 A1 --- Fr- Radiative flux sign 111-130 E20.14 mW/m2 Fr Radiative flux (erg/cm2/s) 133-152 E20.14 g/cm3 rho Gas density 155-174 E20.14 10-7W/cm3 Etot Gas kinetic + internal energy density (erg/cm3) 177-196 E20.14 g Menc Enclosed mass from r=0 to r=ri 199-218 E20.14 cm/s Cs Gas sound speed 221-240 E20.14 K T Gas temperature 243-262 E20.14 g/cm/s P Gas pressure 265-284 E20.14 10-7W/K/g S Gas entropy (erg/K/g) 287-306 E20.14 cm2/g kp Planck mean opacity 309-328 E20.14 cm2/g kr Rosseland mean opacity 331-350 E20.14 --- xH Mass concentration of Hydrogen 353-372 E20.14 --- xH2 Mass concentration of H2 375-394 E20.14 --- xHe Mass concentration of He 397-416 E20.14 --- xHe+ Mass concentration of He+ 419-438 E20.14 s t Time Acknowledgements: Neil Vaytet, neil.vaytet(at)nbi.ku.dk Troels Haugbolle, haugboel(at)nbi.ku.dk
(End) Neil Vaytet [StarPlan, NBI, Denmark], Patricia Vannier [CDS] 04-Nov-2016
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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