In an exciting breakthrough for astronomy and the search for extraterrestrial life, an international team of scientists has announced the discovery of Gliese 12b, a mild Earth-sized exoplanet just 40 light-years away – a relative neighbor of 378 trillion kilometers from Earth.
Researchers from around the world, including key support from researchers at McGill University and Western University, collaborated to find Gliese 12b as part of Subaru’s InfraRed Doppler Strategic Program (IRD-SSP), which searches for planets in the habitable zones around red dwarf stars.
An international team detected the planet’s presence using a combination of advanced telescopes and observational techniques, and its discovery presents exciting opportunities for a deeper understanding of worlds beyond our own solar system.
A planet around a red dwarf
Gliese 12b orbits a central star called Gliese 12, a type of star known as a red dwarf. Red dwarfs are smaller, cooler and more abundant than G-type stars like our Sun.
Planets orbiting red dwarf stars are prime candidates in the search for life beyond Earth. Considerable effort has been made to find planets orbiting red dwarfs, as terrestrial worlds are easier to detect around these stars compared to more massive stars like our Sun.
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Gliese 12 is one of two red dwarf stars—the other being TRAPPIST-1—within 100 light-years of Earth that host Earth-sized planets with relatively minimal stellar radiation. Strong TRAPPIST-1 activity – such as high-energy stellar eruptions – likely disrupts the habitability of its planets, as recent observations suggest that TRAPPIST-1 bac have almost no atmosphere.
Highly active stars show more frequent and intense eruptions and emit life-threatening high-energy radiation than inactive stars. In contrast, Gliese 12 is an unusually inactive red dwarf, meaning its planets face much less damaging conditions.
Barely tepid starlight
What makes Gliese 12 b particularly interesting is its size and location. It is roughly the same size as Earth, suggesting it may have a similar composition and surface environment. However, more observations and modeling are needed to confirm this.
Gliese 12 b’s location near the inner edge of its star’s habitable zone makes it particularly interesting. The habitable zone, often referred to as the “Goldilocks Zone”, is the region around a star where conditions are suitable for the existence of liquid water on the planet’s surface. Since water is essential for life as we know it, finding a planet around this zone is a big step in the search for life.
Gliese 12b receives just enough starlight to be slightly closer than the inner edge of the habitable zone for red dwarfs. However, the actual presence of liquid water depends on its atmosphere and surface conditions. From another perspective, the amount of starlight it receives is between what Earth and Venus get from the Sun. Further study of Gliese 12b could illuminate key differences between habitable Earth and inhospitable Venus.
A closer look
Another interesting aspect of Gliese 12b is that its relatively close proximity to Earth allows for a more detailed study of its surface environment.
One particularly useful method for studying Gliese 12b, which is not possible for non-transiting planets, is atmospheric transmission spectroscopy. This technique involves analyzing the starlight that passes through the planet’s atmosphere during transit. By studying changes in light spectra, scientists can infer the composition of the planet’s atmosphere, identifying gases such as oxygen, water, methane and carbon dioxide, which could indicate biological processes.
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The discovery of Gliese 12b is a stepping stone to finding potentially habitable planets and understanding the conditions that make life possible. Current and future telescopes such as the James Webb Space Telescope and ground-based Extremely Large Telescopes will play a key role in further investigation. These instruments will allow scientists to conduct more detailed studies of the atmosphere and surface conditions of Gliese 12b.
The discovery of Gliese 12b, a nearby possibly habitable exoplanet, is an exciting development in the quest to find Earth-like planets and potentially extraterrestrial life. As we continue to explore space, each new discovery brings us closer to answering the age-old question: Are we alone in space?
For now, Gliese 12b is a beacon of hope and curiosity, inviting us to learn more about the possibilities that lie beyond our own solar system.