New Method Developed: Indian Institute of Astrophysics (IIA) scientists have developed a novel method to accurately estimate Helium abundance in the Sun’s photosphere.
Indirect Spectral Analysis: The method uses spectral lines of neutral Magnesium (Mg I) and neutral Carbon (C I), along with molecular lines of MgH, CH, and C₂ observed in the Sun’s photosphere.
Helium’s Impact on Hydrogen: The method is based on the principle that the relative abundance of Helium affects the availability of Hydrogen, which in turn influences the formation and strength of molecular lines.
Validation of Solar Value: The researchers matched the atomic and molecular abundances of Magnesium and Carbon for different Helium-to-Hydrogen (He/H) ratios, confirming that only at a He/H ratio of ~0.1 do the atomic and molecular line abundances agree.
Challenge Addressed: This new study addresses the challenge of accurately measuring Helium abundance in the Sun’s photosphere, which has been difficult due to the absence of Helium spectral lines.
Agreement with Helioseismology: The derived He/H ratios are in fair agreement with results obtained through helioseismological studies, signifying the reliability and accuracy of the novel technique.
Confirms Widely Assumed Ratio: This study also confirms that the widely assumed and adopted (He/H) ratio of 0.1 is in fair agreement with the measurements.
Potential for Assessing Opacity: This accurate estimation of Helium abundance could be a major step in assessing the opacity of the Sun’s photosphere.