A team of astronomers led by researchers at the University of California, Irvine ( UC Irvine ) has discovered a new Earth-like exoplanet orbiting a star about 25 light-years from our Solar System. The finding, published in The Astrophysical Journal, adds another promising candidate to the growing list of planets that may be capable of supporting life.
Researchers say the newly discovered planet, named GJ 3378b, lies within its star's habitable zone, the region where temperatures could allow liquid water to exist on a planet's surface.
Why is GJ 3378b attracting attention?
According to the researchers, GJ 3378b is around twice the size of Earth and receives nearly the same amount of energy from its host star as Earth receives from the Sun.
"This one's exciting," said Paul Robertson, associate professor of astronomy at UC Irvine and lead author of the study.
"It's one of our closest cosmic neighbors. 25 light-years sounds like a long way, but the Milky Way is about 100,000 light-years across, so in that respect it's our next-door neighbor."
Robertson's team detected the planet using the Habitable-zone Planet Finder on the Hobby-Eberly Telescope in Texas and the NEID Spectrometer on the WIYN Telescope at Kitt Peak National Observatory in Arizona.
Could the planet support life?
Scientists believe GJ 3378b sits comfortably inside the so-called 'Goldilocks zone', where conditions may be suitable for liquid water, considered one of the essential ingredients for life.
"This super-Earth gets about 90 percent of the radiation from its host star as Earth gets from its sun, so it's right in the sweet spot," Robertson said.
While the planet's location makes it an exciting target for future research, scientists say one major question remains unanswered: does it have an atmosphere?
The biggest mystery is its atmosphere
Researchers explained that GJ 3378b lies close to what astronomers call the cosmic shoreline, a region where intense stellar radiation can gradually strip away a planet's atmosphere.
Mars is often cited as an example, with scientists believing it may once have had a much thicker atmosphere before losing most of it over billions of years.
"If you scale the Earth down to the size of an apple, its atmosphere would be about as thick as the skin of the apple," Robertson explained.
"That's just enough to maintain the kinds of surface pressures where you can have liquid water. It's enough that there'll be breathable air, and it provides maybe a little bit of protection from the harsh radiation environment of space."
Future missions could reveal signs of life
Astronomers say confirming whether GJ 3378b has an atmosphere will require next-generation space telescopes.
"If a planet in the habitable zone has a proper atmosphere, we can justify further research looking for biosignatures, liquid water or other signs of life that require both an atmosphere and the right amount of heating from the host star," said Gogod James, a UC Irvine student who helped characterise the planet.
NASA's planned Habitable Worlds Observatory, expected to launch in the 2040s, is designed to image planets like GJ 3378b and determine whether they possess atmospheres. If one is detected, scientists will search for chemical signatures that could point to biological activity.
"I think that's just too much fun," Robertson said.
The research was funded by the National Science Foundation Astronomy & Astrophysics Research Grants and NASA Interdisciplinary Consortia for Astrobiology Research, with contributions from researchers at the University of Texas at Austin, Schmidt Sciences and Pennsylvania State University.
Disclaimer: This article is based on information published by the University of California, Irvine (UC Irvine). Readers are advised to exercise their discretion while interpreting the findings.
