The Chemical Evolution of Helium

  title={The Chemical Evolution of Helium},
  author={Dana S. Balser},
We report on measurements of the He abundance toward the outer Galaxy H II region S 206 with the NRAO Green Bank telescope. Observations of hydrogen and helium radio recombination lines between 8 − 10 GHz were made toward the peak radio continuum position in S 206. We derive He/H = 0.08459 ± 0.00088 (random) ± 0.0010 (known systematic), 20% lower than… CONTINUE READING