Abstract Details
| Name: RULEE BARUAH Affiliation: HRH THE PRINCE OF WALES INSTITUTE OF ENGINEERING A Conference ID: ASI2015_691 Title : BETA DECAY RATES OF SUPERHEAVY ELEMENTS IN EXPLOSIVE ASTROPHYSICAL ENVIRONMENT Authors and Co-Authors : Kalpana Duorah, H. L. Duorah Deptt. of Physics, Gauhati University Abstract Type : Poster Abstract Category : Extragalactic astronomy Abstract : Stars in the mass range 10-30 M⊙ evolve to form iron cores of 1.3 to 1.6 M⊙. These iron cores collapse according to well known instabilities, photodisintegration and electron capture. During collapse an outward bound shock wave forms in the matter falling onto the nearly stationary core. The conditions behind the shock at 100 to 200 km are suitable for neutrino heating . This neutrino heating blows a hot bubble above the protoneutron star and is the most important source of energy for Supernova Explosion . Here we try to attain the r-process (rapid neutron capture process) path responsible for the production of superheavy elements beyond iron , which are otherwise not possible to be formed by fusion reactions . Astrophysical parameters needed for our analysis are temperature (> 109 degrees K) and neutron number density which we take to be greater than 1020 cm-3. In the later expansion stages after SN explosion where the neutron density supposedly falls, the r-process nucleosynthesis produces the heavy elements which subsequently beta decays and the r-process path forms. Along the path , the experimental data of observed elements matches our calculated ones. Later ejecta are neutron-rich (Ye < 0.5) and leaves behind a compact neutron star . We note that the element 98Cf 254 shown by the SN light curves is found in our classical astrophysical condition of T = 1.9× 109 K and nn = 1020 cm-3. Also we note an element of mass 273 corresponding to atomic number 115, at temperature 3.0 × 109 K and neutron density 1020 cm−3. The decay rates of these elements are found to be very much higher than their electron capture rates. KEYWORDS : R-process, nucleosysthesis, interstellar medium. |