New Evidence for the 'Solar Oxygen Crisis'

May 2, 2007 By Laura Mgrdichian feature
The Sun

Scientists have published new evidence supporting the recent discovery that the Sun contains about half as much oxygen as previously thought, an issue some scientists have dubbed the solar oxygen crisis. This is a potentially huge scientific problem because scientists have used the particular prior measurement as a platform for understanding the inner workings of other stars.

Oxygen is the third most abundant atom in the universe and the element most frequently produced in the “nuclear furnaces” of stars. In many astrophysical situations, oxygen is linked to the abundances carbon, nitrogen, and neon. If the oxygen abundance in the Sun is half as much as scientists thought, these other elemental abundances 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,” lead scientist Hector Socas-Navarro, of the National Center for Atmospheric Research, explained to PhysOrg.com. “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.”

In the April 19, 2007, online edition of The Astrophysical Journal, Socas-Navarro and colleague Aimee Norton, a solar physicist at the National Solar Observatory, discuss how they obtained new evidence for the solar oxygen crisis by using a type of light-analysis device to take measurements of infrared and visible light radiating from a patch of the Sun.

The device, known as the Spectro-Polarimeter for Infrared and Optical Regions (SPINOR), attaches to a telescope; in this case, the Richard Dunn Solar Telescope located in Sunspot, New Mexico. The telescope collects the light and sends it to SPINOR, which analyzes its properties. Because 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.

Analysis of the SPINOR data produced a value of the oxygen abundance that agrees with calculations by other research groups studying the solar oxygen crisis. The measurement contained larger-than-expected uncertainty.

“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.

He added that there is another major downside of a lower oxygen abundance. Models of the solar interior once predicted that sound waves in the Sun traveled at certain speed, a value that agreed well with the measured speed. Because the speed depends on composition, this is another way that scientists learn about the processes that take place in the Sun, what elements it is made of, and in what quantities. Now, with the Sun having half as much oxygen, carbon, nitrogen, and neon, the sound speed derived from the models doesn't match the measured speed well.

“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,” he said.

Citation: H. Socas-Navarro and A.A. Norton, “The solar oxygen crisis: Probably not the last word” The Astrophysical Journal, 660:L153-L156, 2007 May 10

Copyright 2007 PhysOrg.com.
All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com.

Explore further: 'Diamonds from the sky' approach turns CO2 into valuable products

Related Stories

Image: The aurora australis over Concordia station

August 19, 2015

It is cold, dark, dry and isolated with very little oxygen to breathe in the air, but the unique location makes Concordia station in Antarctica an attractive place for scientists to conduct research. The aurora australis ...

The planet Mercury

August 6, 2015

Mercury is the closest planet to our sun, the smallest of the eight planets, and one of the most extreme worlds in our solar systems. Named after the Roman messenger of the gods, the planet is one of a handful that can be ...

Venus

July 27, 2015

As the morning star, the evening star, and the brightest natural object in the sky (after the Moon), human beings have been aware of Venus since time immemorial. Even though it would be many thousands of years before it was ...

Sunny, with a chance of nuclear bullets

July 23, 2015

In space, far above Earth's turbulent atmosphere, you might think the one thing you don't have to worry about is weather. But you would be wrong. Just ask the people charged with the safety of the Cloud-Aerosol Lidar and ...

Where is solar power headed?

July 22, 2015

Most experts agree that to have a shot at curbing the worst impacts of climate change, we need to extricate our society from fossil fuels and ramp up our use of renewable energy.

Recommended for you

Seeing quantum motion

August 28, 2015

Consider the pendulum of a grandfather clock. If you forget to wind it, you will eventually find the pendulum at rest, unmoving. However, this simple observation is only valid at the level of classical physics—the laws ...

A little light interaction leaves quantum physicists beaming

August 24, 2015

A team of physicists at the University of Toronto (U of T) have taken a step toward making the essential building block of quantum computers out of pure light. Their advance, described in a paper published this week in Nature ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.