Astronomers detected a narrow radio signal from K2-155, a small red dwarf located 238 light-years away. The signal briefly appeared to be a potential technosignature from an alien civilization before researchers traced it to likely interference.
The detection emerged from archived data gathered by China’s FAST telescope, the world’s largest single-dish radio telescope. Built into a natural basin in southwestern China, the dish measures roughly 1,640 feet across. That vast surface covers an area equivalent to about 30 soccer fields. The instrument spent several months listening for artificial radio signals from 33 known exoplanet systems.
AI Processing Pipeline Flags NBS 260108
An initial 2021 survey found nothing beyond a single false alarm toward Kepler-438b. The software used at that time could only spot rigid, straight-line frequencies. To catch faint or curved signals, a team led by Zi-Qi Li of Beijing Normal University revisited the recordings with a new AI-driven signal processing pipeline known as MSWNet.
The software flagged more than 139,000 signals, dismissing nearly all as interference. Along with re-detecting the known Kepler-438 signal, the AI surfaced just one new candidate of interest. Designated NBS 260108, the signal came from K2-155, a red dwarf hosting three planets larger than Earth, including one near its habitable zone.
The signal showed a steady radio tone concentrated around a single frequency. Its frequency also shifted steadily downward over time. Natural cosmic processes rarely produce such narrow broadcasts, making them targets in the search for extraterrestrial technology.
Data Discrepancies Point to Terrestrial Interference
The signal stood out because it appeared only in the telescope beam aimed directly at K2-155. It did not register in the other 18 receiver beams during the September 10, 2021, observation sequence. That sequence also included observations of the stars K2-18, GJ-9066, and Ross 128.
Despite those promising traits, the team found reasons to doubt an extraterrestrial origin. The signal was much stronger in one polarization channel than the other. When the two channels were combined, that measurement was approximately 15. Similar narrow radio features appeared near three other stars during the same observing run, proving the broadcast did not originate from a single planetary system.
Researchers detailed their findings in a study published in The Astronomical Journal titled ‘A Wavelet-Integrated Search Pipeline for Narrowband Technosignatures in FAST Observations of 33 Exoplanet Systems’. They concluded that Earth-based radio interference or internal equipment trouble was the most likely cause of the reading.
Questions About the K2-155 Signal Search
What makes K2-155 an interesting target for astronomers?
K2-155 is a red dwarf system located 238 light-years from Earth that hosts three super-Earth planets. One of these planets orbits close to the habitable zone where liquid water could exist.
How large is the FAST telescope dish?
The FAST telescope features a dish measuring roughly 1,640 feet across, built into a natural basin in southwestern China. Its collecting surface covers an area equivalent to about 30 soccer fields.
What are the next steps for the research team?
The team plans to analyze raw voltage data across all 19 of the telescope’s receiver beams to calculate the exact source position. This step aims to definitively rule out human-generated interference.
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