2018MNRAS.479L..60N -
Mon. Not. R. Astron. Soc., 479, L60-L64 (2018/September-1)
Collision strengths for FIR and UV transitions in P III and the phosphorus abundance.
NAGHMA R., NAHAR S.N. and PRADHAN A.K.
Abstract (from CDS):
Phosphorus abundance is crucial for DNA-based extraterrestrial life in exoplanets. Atomic data for observed spectral lines of P-ions are needed for its accurate determination. We present the first calculations for collision strengths for the forbidden [P III] fine structure transition 3s23p(2Po1/2–3/2^) within the ground state at 17.9 µm , as well as allowed UV transitions in the 3s23p(2Po1/2,3/2^) →3s3p2(2D3/2,5/2, 2S1/2, 2P1/2,3/2) multiplets between 915 and 1345 Å. Collision strengths are computed using the Breit-Pauli R-Matrix method including the first 18 levels, and they exhibit extensive auto-ionizing resonance structures. In particular, the Maxwellian averaged effective collision strength for the FIR 17.9 µm transition shows a factor 3 temperature variation broadly peaking at typical nebular temperatures. Its theoretical emissivity with solar phosphorus abundance is computed relative to H β and found to be similar to observed intensities from planetary nebulae; the abundances derived in earlier works are 3-5 times sub-solar. The results pertain to the reported paucity of phosphorus from preferred production sites in supernovae, and abundances in planetary nebulae and supernova remnants.
Abstract Copyright:
© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
Journal keyword(s):
astrobiology - atomic processes - ISM: atoms - ISM: supernova remnants - ISM: nebulae - infrared: general
Simbad objects:
4
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