(GIST OF SCIENCE REPORTER) SOLAR IRON OPACITY

(MAY-2025)

SOLAR IRON OPACITY

Context:

In a groundbreaking discovery, scientists from the Sandia National Laboratories (USA), along with French researchers, have confirmed a long-standing mystery in astrophysics: the element iron inside the Sun’s interior is far more opaque (less transparent) than our current scientific models have predicted. This breakthrough is helping scientists rethink how energy flows inside stars like our Sun.

Why Is This Important for Science? 

1. Affects Stellar Models:  

• When iron’s opacity is underestimated, it gives a wrong picture of energy transport inside stars. This means we can’t accurately simulate how stars burn, shine, and evolve.

2. Impacts Broader Astrophysics:

• Exoplanets: Predictions about which planets might support life depend on understanding their host stars.

• Supernovae: Star explosions are linked to how energy flows in their core.

• Galactic Chemistry: The creation of new elements in stars (called nucleosynthesis) relies on correct models of stellar interiors.

So, solar opacity isn’t just about the Sun — it’s about understanding the entire universe.

What is the Sun?

The Sun is a 4.5-billion-year-old yellow dwarf star, made mostly of hydrogen and helium. It lies at the center of our solar system and provides the energy that makes life on Earth possible. Science of the Sun: Heliophysics

The study of the Sun and how it affects the rest of the solar system is called heliophysics.

Structure of the Sun: From Core to Corona

Let’s look at the Sun from the innermost to outermost layers:

1. Core:

• The Sun’s energy is produced here through nuclear fusion.  

• Temperature: around 15 million °C.

2. Radiative Zone:

• Energy moves outward slowly through radiation.

3. Convective Zone:

• Energy moves in the form of hot, rising gas (convection).

4. Photosphere (Visible Surface): 

• What we see as the “surface” of the Sun.

• Temperature: about 5,500 °C

5. Chromosphere: A reddish layer visible during solar eclipses.

6. Transition Zone: A thin, uneven layer between chromosphere and corona. 

7. Corona (Outer Atmosphere):

• Surprisingly, it’s hotter than the surface, reaching up to 2 million °C

• One of the biggest mysteries in solar physics.

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Courtesy: Science Reporter