RADIOACTIVE MOLECULES IN SN1987A REMNANT

Анотація

The  investigation  of  SN1987A remnant  is  complicated  due  to  absence  of  the  source  of ionizing radiation,  which should excite the remnant’s atoms and molecule. X-ray radiation from the shock wave front and, in accordance with recent observations, the intensity  of  X-rays  significantly  decreased  during  the  last year made the backlighting of remnant. At the same time the  intensity  of  molecular  lines  emission,  localized  near the  front,  abruptly  increased.  The  remnant  itself  can  be  detected  at  the  longer  wavelength  due  to  IR  emission  of  dust component. One of the outburst’s results was the synthesis  of  radioactive  isotope ⁴⁴₂₂Ti  Its  decay  time  is  85 years, the total mass of synthesized atoms is near the mass of Jupiter. The thermochemical analysis shows that during the  last  two  years  the  remnant  creates  a  set  of  diatomic  molecules, which will be not a subject of thermal dissociation later. One of these molecules is the radioactive titanium oxide ⁴⁴₂₂Ti¹⁶₈O.  We  investigate  the  properties  of  diatomic  molecules ⁴⁴₂₂Ti¹⁶₈O and ⁴⁴₂₁Sc¹⁶₈O  before and after the radioactive decays of ⁴⁴₂₂Ti  and  ⁴⁴₂₁Sc. For oxides  ⁴⁴₂₂Ti¹⁶₈O and ⁴⁴₂₁Sc¹⁶₈O the spectroscopic constants were calculated using the isotopic  shifts  with  respect  to  well  known ⁴⁴₂₂Ti¹⁶₈O and ⁴⁴₂₁Sc¹⁶₈O molecules. The isotope ⁴⁴₂₂Ti  captures the electron from internal level. The result is the synthesis of new molecule ⁴⁴₂₁Sc¹⁶₈O. ⁴⁴₂₁Sc decays after 6 hours and creates the stable isotope ⁴⁴₂₀Ca, hard X-ray and γ -quanta and positron (e+). Additional result is the dissociation of molecule and the  synthesis  of  stable  neutral  isotope ⁴⁴₂₀Ca   after  the  sequence of decays  ⁴⁴₂₂Ti → ⁴⁴₂₁Sc ^{→  44}₂₀Ca. We found the energetic properties of transient molecules ⁴⁴₂₂Ti¹⁶₈O and ⁴⁴₂₁Sc¹⁶₈O. We first estimated the probabilities of radioactive transitions in the molecule ⁴⁴₂₂Ti¹⁶₈O  during its transition to ⁴⁴₂₁Sc¹⁶₈O. We calculated the molecular transitions  which  allow  to  point  the  electronic,  vibrational  and rotational  transitions  during  the  decay ⁴⁴₂₂Ti → ⁴⁴₂₁Sc.  The  obtained results permit us to predict the new spectral lines and bands detection in the spectrum of SN1987A remnant. It will be emitted by transient molecules and can be identified in future observations.