Solar Oxygen Crisis Confirmed

Oxygen (O) is essential for cellular respiration of all organisms that use air. It is the third most abundant chemical element in the universe by mass, after hydrogen and helium, and the most important on Earth.

Scientists have published new strong evidence that the Sun contains nearly half as much oxygen as previously thought, a find that some scientists have dubbed "the solar oxygen crisis."

As oxygen is primarily produced in massive stars, it's closely linked to the formation of carbon, nitrogen and neon. If the oxygen levels on the Sun are, indeed, half as low as previously estimated, the abundance of other elements may also be off by a factor of two.

"The abundance of solar oxygen serves as a key reference for the chemical composition of other stars," said lead scientist Hector Socas-Navarro, of the National Center for Atmospheric Research. "We thought we had very solid measurements of this abundance since the 1980s, but recent evidence indicates that we've been overestimating it by almost a factor of two. The implications of this are incredibly important."

Until now, scientists have been using the classical values for measurements (it was thought that the Sun contained around 0.77% oxygen) to help them understand the internal processes of other stars.

Using a device known as the Spectro-Polarimeter for Infrared and Optical Regions (SPINOR), attached to the Richard Dunn Solar Telescope located in Sunspot, New Mexico, astronomers have collected light coming from the Sun and analyzed its properties.

Since atoms in the Sun emit light at very specific wavelengths, the researchers can calculate the abundances of various elements by measuring the wavelengths of light rays coming in.

The result was a value of the oxygen abundance that agrees with calculations by other research groups studying the solar oxygen crisis, so it seems it's real.

"This measurement is more uncertain than we thought it would be, which is one of the interesting conclusions of our particular work," said Socas-Navarro. "Exactly what this means is not very clear, but it casts doubt on the correctness or at least the accuracy of models of stellar interiors, which are a cornerstone of modern astrophysics,"

Other applications could be affected too, like the sound speed derived from the earlier models, which doesn't match well the measured speed.