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3 results

  • 22 - Star Formation

  • from Part III - Interstellar Medium and Formation of Stars and Planets
  • Stan Owocki, University of Delaware
  • Book:
    Fundamentals of Astrophysics
    Published online:
    08 October 2021
    Print publication:
    03 June 2021, pp 162-170

  • Summary

    Stars generally form in clusters from the gravitational contraction of a dense, cold giant molecular cloud. We explore the critical requirement for such contraction, known as the Jeans criterion, and the factors that affect the star formation rates and the initial mass function in star clusters and galaxies. We finish by looking at how the conservation of angular momentum can lead to proto-stellar disks, with important implications for forming planets.

  • Modelling the emission of nitrogen-bearing molecules towards the solar type protostar IRAS16293-2422

  • A. Hernández-Gómez, E. Caux, L. Loinard, S. Bottinelli
  • Journal:
    Proceedings of the International Astronomical Union / Volume 13 / Issue S332 / March 2017
    Published online by Cambridge University Press:
    04 September 2018, pp. 425-428
    Print publication:
    March 2017
    • Article
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  • Nitrogen, one of the most abundant elements in the Universe is a fundamental element of molecules which are crucial for life. We present here the modelling of the emission of two of the simplest nitrogen-bearing molecules, CN and NO, with a non-LTE radiative transfer code in IRAS16293-2422, a class 0 low-mass protostar. In this model, we assumed IRAS16293-2422 is formed by 2 compact, hot and dense sources embedded in a three layers of envelope.

  • Modelling the emission of HNCO towards IRAS16293-2422 using a new set of collisional coefficients

  • Hernández-Gómez A., Sahnoun E., Caux E., Wiesenfeld L., Loinard L., Bottinelli S., Hammami K.
  • Journal:
    Proceedings of the International Astronomical Union / Volume 13 / Issue S332 / March 2017
    Published online by Cambridge University Press:
    04 September 2018, pp. 435-439
    Print publication:
    March 2017
    • Article
      • You have access
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  • Isocyanic acid (HNCO) is a simple molecule containing the four main atoms essential for life and can be considered as a prebiotic molecule. To model the HNCO emission in the IRAS16293-2422 class 0 low-mass protostar, we used a new set of HNCO collisional coefficients with ortho-H2 and para-H2, computed from a set of rotational excitation quenching rates between HNCO and H2 based on a novel potential energy surface for the rigid molecules interactions. We present here the HNCO Potential Energy Surface used to compute this new set of collisional coefficients and the result of the IRAS16293-2422 HNCO spectrum modelling using them.