Astronomers are abuzz with the recent discovery of Gliese 12 b, an exoplanet (planet outside our solar system) that’s tantalizingly close to Earth — a mere 40 light-years away.
What makes this distant world so exciting?
It’s not just the Earth-to-Venus size or the potential 107°F (42°C) temperature that makes Gliese 12 b interesting. The real intrigue lies in what this planet might teach us about how planets retain or lose their atmospheres.
Gliese 12 b exoplanet for atmospheric studies
Why is Gliese 12 b so perfect for studying planetary atmospheres? A few reasons include:
Right size of exoplanet
Gliese 12 b is roughly the size of Earth or slightly smaller, making it comparable to Venus. This similarity in size makes Gliese 12 b an excellent subject for studying rocky planets.
Understanding its characteristics can help scientists draw comparisons between Earth, a habitable planet, and Venus, which is inhospitable due to its extreme greenhouse conditions.
These comparisons are crucial for learning about the different evolutionary paths rocky planets can take.
Exoplanet Gliese 12 b has a red dwarf star
Gliese 12 b orbits a red dwarf star, significantly smaller and cooler than our Sun. Red dwarfs have lower luminosity, which means their habitable zones are much closer to the star. This proximity allows for a more detailed study of planets within these zones.
The star’s smaller size and mass also make it easier to detect planets like Gliese 12 b through the transit method. Each transit causes a more noticeable dimming of the star’s light, and the planet’s gravitational pull induces a detectable wobble in the star, known as reflex motion.
Temperate conditions
The estimated surface temperature of Gliese 12 b is 107°F (42°C), assuming it has no atmosphere. If an atmosphere is present, it could moderate the temperature, making the planet even more suitable for liquid water.
The presence and composition of an atmosphere are key factors in determining a planet’s habitability. Atmospheric studies can reveal if Gliese 12 b has conditions that might support life, or if it resembles Venus, with a thick, inhospitable atmosphere.
Close proximity to Earth
Gliese 12 b is located 40 light-years away, which is relatively close in astronomical terms. This proximity makes it easier for advanced telescopes, such as the James Webb Space Telescope, to observe the planet in detail.
Detailed observations can include studying the planet’s atmosphere through transmission spectroscopy during transits.
By analyzing the starlight that passes through the planet’s atmosphere, scientists can identify the chemical composition and determine the presence of gases like water vapor, carbon dioxide, and methane.
This data is essential for assessing the planet’s potential for habitability and understanding the atmospheric processes at play.
Potential for new discoveries
Gliese 12 b’s characteristics make it a prime target for future studies. Its Earth-like size, orbit around a cool red dwarf, and relatively close proximity provide a unique opportunity to learn more about planetary atmospheres and the conditions necessary for habitability.
Research on Gliese 12 b could offer insights into how planets retain or lose their atmospheres, shedding light on the factors that make planets like Earth habitable and others like Venus inhospitable.
This knowledge not only enhances our understanding of exoplanets but also contributes to our knowledge of the formation and evolution of planets in our own solar system.
Exo-venus connection
Researchers are likening Gliese 12 b to an “exo-Venus.”
“It is thought that Earth’s and Venus’s first atmospheres were stripped away and then replenished by volcanic outgassing and bombardments from residual material in the solar system,” explains Larissa Palethorpe, a doctoral student involved in the research.
But why is Earth a paradise and Venus an inferno? Palethorpe suggests that Gliese 12 b, sitting between Earth and Venus in terms of temperature and solar radiation, might help us understand how some planets lose their water and become uninhabitable while others remain oases.
Peering into the atmosphere
So, how do we figure out if Gliese 12 b has an atmosphere, and what it’s made of? Enter the transit method. As the planet passes in front of its star, the star’s light filters through the planet’s atmosphere (if it has one).
Different gases absorb specific wavelengths of light, creating a unique fingerprint that telescopes like the James Webb can analyze.
“We know of only a handful of temperate planets similar to Earth that are both close enough to us and meet other criteria needed for this kind of study, called transmission spectroscopy, using current facilities,” notes Michael McElwain, a research astrophysicist at NASA.
“To better understand the diversity of atmospheres and evolutionary outcomes for these planets, we need more examples like Gliese 12 b.”
Significance of discovering exoplanet Gliese 12 b
The discovery of Gliese 12 b is a chance to peer into the past and future of our own solar system. It’s also a step towards understanding what makes a planet habitable, and whether such worlds are common in the cosmos.
“Gliese 12 b represents one of the best targets to study whether Earth-size planets orbiting cool stars can retain their atmospheres, a crucial step to advance our understanding of habitability on planets across our galaxy,” concluded Shishir Dholakia, another researcher involved in the study from the Centre for Astrophysics at the University of Southern Queensland in Australia.
The mystery of Gliese 12 b is just beginning to unfold. With powerful telescopes like the James Webb Space Telescope trained on it, we’re on the verge of uncovering secrets that could reshape our understanding of planetary evolution and the potential for life beyond Earth.
