Our Galaxy hosts the annihilation

Discussion in 'Astronomy, Exobiology, & Cosmology' started by wangchaoqing, Jun 8, 2018.

  1. wangchaoqing Registered Member

    Our Galaxy hosts the annihilation of a few 10^43 low-energy positrons every second. Radioactive isotopes capable of supplying such positrons are synthesized in stars, stellar remnants and supernovae. For decades, however, there has been no positive identification of a main stellar positron source, leading to suggestions that many positrons originate from exotic sources like the Galaxy’s central supermassive black hole or dark matter annihilation. Here we show that a single type of transient source, deriving from stellar populations of age 3–6 Gyr and yielding ∼0.03M ⊙ of the positron emitter 44-Ti, can simultaneously explain the strength and morphology of the Galactic positron annihilation signal and the Solar System abundance of the 44-Ti decay product 44-Ca. This transient is likely the merger of two low-mass white dwarfs, observed in external galaxies as the sub-luminous, thermonuclear supernova known as SN 1991bg-like.

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  3. NotEinstein Valued Senior Member

    Is there anything you want to discuss? You've just copy-pasted the abstract of the article (without attribution, which is frowned upon on this forum), and posted a link.
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