Sun May Have Swallowed 5–10-Earth-Mass Planet, Study Finds

A newly published study proposes that the Sun may have engulfed a massive exoplanet during its youth — an event researchers describe as a “cosmic crime” whose evidence could still reside deep inside our star today.

What the study proposes

The research identifies a potential explanation for the absence of super-Earths — rocky, extrasolar planets with masses greater than Earth’s but substantially less than those of gas giants like Neptune or Uranus — within our own solar system. Such worlds are commonly observed orbiting other stars.

Motlu Yıldız of Ege University in Turkey stated: “Our study indicates that a planet several times more massive than Earth may have fallen into the young Sun and left a permanent chemical signature in its depths.”

How the hypothesis addresses solar anomalies

Scientists note that the Sun exhibits discrepancies between observed properties and predictions from standard stellar evolution models. These include variations in the depth of the Sun’s convective zone, the structure of sound-speed profiles beneath the surface, and the notably low abundance of lithium at the solar surface.

The team hypothesizes that early planetary ingestion could account for these mismatches. Young stars like the Sun are surrounded in their infancy by broad, flattened disks of gas and dust known as protoplanetary disks, where substantial material exchange can occur between the disk and the central star.

Yıldız explained: “Since planets are composed of chemically distinct material compared to the gas in the disk, we asked whether early planetary accretion might have left a chemical imprint within the Sun.”

Computational modeling yields precise mass range

Using advanced software, the research team tested this hypothesis against current solar characteristics. Their simulations determined that the best match for present-day solar data is a scenario in which the Sun consumed a planet with a mass between five and ten times that of Earth.

Professor Yıldız added: “We expected planetary ingestion to affect the Sun’s structure, but we did not anticipate that the calculations would converge so precisely on a specific mass range.”

Broader context and open questions

This work aligns with earlier studies suggesting that one or more super-Earths may have formed near Mercury’s current orbit before migrating inward and ultimately colliding with the Sun. However, the new analysis does not rule out alternative explanations for the observed solar inconsistencies.

The hypothesis currently rests on computer modeling and unresolved solar properties. Researchers believe structural and chemical traces of such an ingestion event may still persist inside the Sun and could be detectable through future observational techniques. Yıldız concluded: “The next step is to determine whether these imprints can be detected independently.”

The findings appeared in the journal *Monthly Notices of the Royal Astronomical Society*.