Researchers Identify Nearby Super-Earth as Prime Life Candidate

Astronomers at the University of California – Irvine have discovered a super-Earth located in the habitable zone of a nearby M-dwarf star, approximately 18 light-years from Earth. This discovery positions the planet, named GJ 251 c, as a significant target in the ongoing search for extraterrestrial life, primarily due to its potential to host liquid water.

The habitable zone is defined as the region around a star where conditions could allow for the presence of liquid water on a planet’s surface. Liquid water is deemed essential for all known forms of life, making GJ 251 c an intriguing object of study. The planet is classified as a super-Earth, exhibiting a rocky composition that is several times more massive than our own planet.

Characteristics and Discovery of GJ 251 c

The research team, including co-author Paul Robertson, an associate professor of physics and astronomy at UC Irvine, has shared their findings in a paper published in The Astronomical Journal. Robertson highlighted the significance of the planet’s proximity. “What makes this especially valuable is that its host star is close by,” he noted, emphasizing that, cosmically speaking, it is “practically next door.”

GJ 251 c orbits an M-dwarf star, one of the most common and oldest types of stars in the Milky Way. These stars often exhibit considerable activity, such as starspots and flares, which can create challenges in detecting orbiting planets. Despite these complications, the planet’s relative closeness to Earth makes it an excellent candidate for future direct imaging.

The Thirty Meter Telescope (TMT), currently under development, may enable astronomers to directly observe GJ 251 c. Its large mirrors will allow for the detection of faint worlds, potentially revealing whether liquid water is present on its surface. “TMT will be the only telescope with sufficient resolution to image exoplanets like this one,” stated Corey Beard, a data scientist and lead author of the study.

Advanced Techniques for Exoplanet Detection

The discovery of GJ 251 c was made possible through data collected by the Habitable-zone Planet Finder and NEID, two precision instruments that measure the gravitational effects an orbiting planet exerts on its star. These tools detect small, periodic shifts in the star’s light, known as radial velocity signatures. Such measurements confirmed that GJ 251 c is indeed influencing its star.

HPF, in particular, helps mitigate the effects of M-dwarf stellar activity by observing in the infrared spectrum, where disruptive signals from the star are less pronounced. As the research team refined their computational models, they reached a statistically significant level of confidence in classifying GJ 251 c as a viable exoplanet candidate.

While the discovery is a noteworthy achievement, Beard emphasized the need for next-generation telescopes to verify the planet’s properties through direct imaging. “We are at the cutting edge of technology and analysis methods with this system,” he remarked. The team hopes their findings will inspire further exploration of GJ 251 c, especially as new observatories, such as the TMT, approach operational readiness.

Collaborators on this important research include experts from various institutions, such as Jack Lubin of UCLA, Eric Ford and Suvrath Mahadevan from Pennsylvania State University, Gudmundur Stefansson from the University of the Netherlands, and Eric Wolf from the University of Colorado, Boulder.

The research received funding from the National Science Foundation (NSF) grant AST-2108493 for the HPF exoplanet survey and the NASA/NSF NN-EXPLORE program. As the scientific community continues to explore the cosmos, the discovery of GJ 251 c represents another step toward understanding the potential for life beyond our planet.