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The Sun Is an Ordinary Star: How We Found Out

Original: "The Sun's chemical peculiarity: disentangling Galactic chemical evolution and planetary engulfment in solar twins"
arXiv:2607.01699v1 · 2026-07-02 · CC BY · ⏱ 2 min · Stellar Exoplanets
Scientists realized: the Sun's chemical portrait is explained by the Galaxy's evolution, not because it avoided devouring planets.
Abstract

Scientists compared the chemical makeup of the Sun with 79 similar stars—so-called 'solar twins.' It turns out the small differences aren't because the Sun 'swallowed' planets but are down to ordinary galactic evolution. That makes our Sun a pretty ordinary star. It's like spotting your lookalike in a crowd: a few minor traits differ, but the core is the same.

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Imagine you're proud of your family's bread recipe, and then you find out: exactly the same bread is baked all over your home village—just using local flour and starter. That's roughly what astronomers figured out about the Sun. For a long time, it was thought that our star was chemically unusual — it has fewer heavy elements than its 'twins'. The idea was that other stars 'ate' their planets and got heavier, while the Sun stayed pure.

The precision of the research is stunning: it's like finding one extra grain of salt in a huge Olympic swimming pool. The reference for comparison was sunlight reflected from the asteroid Vesta — a perfect natural mirror.

After studying 79 solar twins, scientists used spectroscopy — a method that splits light like a rainbow to read its chemical makeup. It turned out that the key to the puzzle is the evolution of the Galaxy. After the Big Bang, the cosmos was filled only with light hydrogen and helium, and heavy elements like iron and carbon built up gradually, born in supernova explosions. Stars that formed later and in other parts of the Galaxy automatically got more of this 'seasoning'. So when scientists account for this natural variation, nearly two-thirds of the twins stop looking different from the Sun. And only very few — just a handful out of 79 — showed traces of past 'devouring' of exoplanets. So the Sun is just an ordinary star of its generation, and its chemical portrait isn't random at all but determined by its birthplace and time.

As early as the 1920s, Cecilia Payne-Gaposchkin first realized that stars are made almost entirely of hydrogen, and later Fred Hoyle and Margaret Burbidge revealed how stars create carbon, oxygen, and iron inside them.

🎯 The measurement accuracy was so high that scientists could detect a change in a star's chemical makeup equivalent to one extra grain of salt in an Olympic swimming pool.

🎬 In the science fiction series 'Star Trek', they showed a star swallowing an entire planet. As it turns out, in reality, this sometimes happens, but it leaves only a barely noticeable chemical trace.

A(\mathrm{X}) \equiv \log_{10}(N_\mathrm{X}/N_\mathrm{H}) + 12
Number characterizing the element's concentration relative to hydrogen.
\Delta \ln Z = \ln Z_\text{model 1} - \ln Z_\text{model 2}
A measure of statistical preference for one model over another.
Scientists
Alan GuthAndrei LindeGeorges LemaîtreJames PeeblesAdam RiessBrian Schmidt
Tags
Sun spectroscopy exoplanet galaxy hydrogen carbon big bang supernova
Laws
Friedmann equationsHubble's lawDoppler effectKepler's third lawCoulomb's lawEinstein field equations
Original: arXiv:2607.01699v1 · CC BY · bridge42worlds