New research suggests that the telescope could be poised to detect an Earth-sized planet orbiting Proxima Centauri, our nearest stellar neighbor, just over four light-years away. While we’ve long known about Proxima b, an already confirmed rocky planet in the star’s habitable zone, this new study is shifting the focus toward the possibility of a second, smaller, Earth-like world hidden in the glare of the star.
It’s a tantalizing possibility: what if, just a stone’s throw away in cosmic terms, there’s another planet with conditions that could support life? The search for another Earth has captured humanity’s imagination for years, and now, with the JWST’s advanced capabilities, we might finally have the technology to find one.
Proxima Centauri: A Prime Target for Planetary Exploration
Proxima Centauri, a red dwarf star, is the closest stellar neighbor to our Sun, but it’s nothing like our bright, burning ball of light. Smaller, cooler, and much dimmer, Proxima Centauri offers astronomers an interesting opportunity: it’s the perfect kind of star for spotting planets.
According to the research, red dwarfs are far more likely to reveal the presence of planets because their faint light allows even small, distant worlds to shine through. However, there’s a catch, these stars also tend to erupt with powerful flares that could potentially strip away the atmospheres of planets orbiting too closely.
Still, Proxima Centauri remains a key focus for scientists searching for habitable planets. The star’s proximity makes it an ideal candidate for JWST’s infrared instruments to test the limits of planet detection. And although Proxima Centauri is a less-than-ideal host for life as we know it, its proximity to Earth, just a few light-years away, gives it a special place in the hearts of astronomers.
Howdy, neighbor! 👋
The star closest to our Sun, Proxima Centauri, also hosts the closest exoplanet to Earth, only 4.2 light-years away. The small star is hard to see, but now there’s more reason to look! A possible second planet, Proxima Centauri c, is awaiting confirmation! pic.twitter.com/jFlDOTHMhT
— ARCHIVED NASA Exoplanets (@NASAExoplanets) January 21, 2023
JWST’s Pioneering Search for a Hidden Earth
JWST is equipped with technology that makes it perfect for hunting down faint signals from distant planets. Its Mid-Infrared Instrument (MIRI) is capable of detecting the heat signatures of planets that are too small or too distant to be seen with traditional telescopes.
In a recent study, published in Icarus, scientists simulated how JWST could potentially spot a planet near Proxima Centauri. They used MIRI’s coronagraph, which blocks out the overwhelming light from the star to reveal the faint glow of a nearby planet.
Researchers tested various models of planets orbiting Proxima Centauri at distances between 0.1 and 1 arcsecond—a region where liquid water could exist. While JWST can detect planets that are a bit larger than Earth, its ability to detect planets of Earth’s size remains limited. The primary challenge? The immense glare from Proxima Centauri itself.
The closer a planet is to the star, the harder it is for JWST to detect it because the star’s brightness drowns out the faint heat signals from the planet. However, the team found that planets with temperatures higher than 400 K could still emit enough radiation to be picked up by JWST under near-perfect conditions.
Schematic of remaining liquid in the pore space of frozen soil. Credit: Icarus
What’s Next for Planet Detection?
According to the study, smaller, cooler planets are tough to detect because their heat emissions are too faint compared to the star’s bright light. However, warmer planets, especially those about 1.5 to 2 times the size of Earth, are more likely to stand out in the infrared spectrum.
This doesn’t mean that the search for a second Earth is over. Quite the opposite. The data JWST is collecting will be invaluable for future space telescopes and missions. In fact, upcoming observatories like LUVOIR and HabEx are designed to carry even more advanced instruments to study planets in more detail.