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Non-Primordial Deuterium Production by Accelerated Particles

This scientific study explores the production of deuterium through accelerated particles. The research aims to understand the variations in local interstellar medium and the potential significance of flares as sources of deuterium. The study also examines the production of other elements in flares and investigates the gamma-ray constraint on deuterium. The conclusion reinforces the argument made by Epstein et al. (1976) that local deuterium variations cannot be solely explained by clumps of flare stars.

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Non-Primordial Deuterium Production by Accelerated Particles

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  1. On Non-Primordial Deuterium Production by Accelerated ParticlesbyTijana ProdanovićBrian D. FieldsUniversity of Illinois at Urbana-Champaign

  2. Why Should We Care about D? • Epstein et al. (1976) – Deuterium only produced in Big Bang • Monotonic decline! can measure primordial abundance • But variations in local ISM !? Mullan & Linsky (1998) say: Epstein et al. (1976) neglected radiative capture of n n + p  d +  capture high p density  Flares can be significant sources of D • Can they really?

  3. The Plan Two ways to test ML: • Stick with the basic particle physics and see how many neutrons can flares make • predict a flux and look for 2.22 MeV  rays

  4. Element Production in Flares • Thick target model: spectrum of projectiles is modified – ionization energy losses • Particle production via spallation i + j  l + … (eg. p+n+…) • Projectile spectrum reasonable (solar) s  4  1 • Results: n/p  1 but 6Li/(n+d) 500 (6Li/d)solar making d overproduces 6Li

  5. Gamma-Ray Constraint Expect: • Radiative capture: • 2.223 MeV  ray intensity : Expected lower limit (Galactic d destruction = production): I > 5  10-2 cm-2 sec-1 sr-1 Butwe see: I < 5  10-4 cm-2 sec-1 sr-1 IR image by COBE (K giants) But we see: McConnell et al. (1998)

  6. Conclusion • Flares do not produce much more n’s than d, and they also produce enough 6Li  Epstein et al. (1976) argument holds! • From COMPTEL we see what flare stars do: • Not even clumps of flare stars can be the answer to local deuterium variations

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