ASTRONOMERS have discovered possibly two gas giant planets orbiting a red dwarf star 30 light years from Earth – a find that could challenge understanding about how planets form.

Researchers from the Carmenes consortium, led by Dr Juan Carlos Morales, from the Institute of Space Studies of Catalonia (IEEC), used a technique that monitors a star’s back-and-forth movement when it is orbited by one or more planets.

The star, however, almost did not make it onto their list of observational targets.

IEEC director and project scientist, Ignasi Ribas, said: “Initially, this star was not included in our observation list because it was too faint. We then realised we didn’t have enough small stars in the sample and we added a few, at the very last minute. We were lucky to do so because otherwise we would have never made this discovery.”

The team’s observations revealed a motion caused by a massive companion in both the optical and infrared arms of the Carmenes spectrograph, which is located at the Calar Alto Observatory in southern Spain (pictured). Ansgar Reiners, from the Institute for Astrophysics in Gottingen, said: “Despite the fact that optical high-resolution and stabilised spectrographs have existed for a while … near-infrared ones represent a new technology.”

Morales said: “The star was showing a rather strange behaviour very early on. Its velocity was changing very rapidly, and consistently in both wavelength channels of the instrument, indicating the presence of a massive companion, an anomalous feature for a red dwarf.”

Gas giant planets, such as Jupiter or Saturn, are understood to have formed from rocky cores, which then form a nucleus.

When a critical mass is reached, they begin to accumulate and retain large amounts of gas.

Alexander Mustill, a senior research fellow at Lund Observatory, said: “After running multiple simulations ... we concluded that our most up-to-date models could never allow the formation of even one massive planet, let alone two.”

This discovery suggests that gas giant planets can form through the self-accumulation of gas and dust instead of needing a “seed” core.

Morales added: “I find it fascinating how a single anomalous observation has the potential to produce a paradigm shift in our thinking, in something as essential as the formation of planets and, therefore, in the big picture of how our own solar system came into existence.”