What this research found
NASA's catalogue of 6,061 confirmed exoplanets was narrowed to the 124 sitting inside a conservative habitable zone, then ranked for James Webb Space Telescope (JWST) atmospheric follow-up by combining spectroscopy signal strength, a penalty for atmospheric stripping by active host stars, and JWST's real pointing constraints across 2026 and 2027. Rocky planets around M-dwarfs came out ahead even after a 50% stripping penalty, with a median adjusted transmission metric 33.6 times higher than K- and G-dwarf alternatives (p = 0.009). Scheduling reality then removed several of the best of them, Proxima Centauri b included, leaving 30 actionable targets.
- Habitable zone planets are scarce. Requiring 0.25 to 1.75 times Earth's insolation flux left 124 candidates out of 6,061 confirmed planets, or 2.05%, split across 50 M-dwarf, 46 K-dwarf, 25 G-dwarf, and 2 F-dwarf hosts.
- M-dwarf rocky planets remain the better bet. A Mann-Whitney U test on planets under 1.6 Earth radii found a median adjusted transmission metric of 7,930.78 for M-dwarf hosts against 235.65 for non-M-dwarfs — a 33.6-fold gap, p = 0.009, with a common-language effect size of 0.905 — even after halving M-dwarf scores for stripping risk.
- Telescope access, not signal strength, is the binding constraint. Median visibility across the sample is 0.0 days per year against a mean of 84.8, only 24 targets (19.5%) exceed 200 days per year, and just 30 of the top 50 are visible at all during 2026 and 2027.
- The strongest signal in the catalogue is unusable for now. Proxima Centauri b has the highest raw transmission metric at 177,795.16 (88,897.6 adjusted) but zero visibility days in this window, as do TOI-2134 c, which has the sample's highest emission metric at 4.02, and Wolf 1061 c.
- The stripping penalty reshuffles the middle of the list without changing the top: M-dwarfs drop an average of 4.4 positions, K-dwarfs gain 0.5, and G-dwarfs gain 7.8, with Kepler-1229 b falling 29 places, yet M-dwarfs still occupy nearly every leading rank.
- Teegarden's Star b heads the observable list — a 1.05 Earth-radius M-dwarf planet with an adjusted transmission metric of 38,207.7 and 105 visibility days per year opening in June 2027 — while GJ 1061 c and d offer 365-day-per-year access from January 2026.
How it was done
The NASA Exoplanet Archive's composite planetary parameters table was filtered to planets receiving 0.25 to 1.75 times Earth's insolation flux, leaving 124 habitable zone candidates, 123 of which had measured masses. Transmission and emission spectroscopy metrics were computed for each, then multiplied by a retention score keyed to host-star temperature — 0.5 for M-dwarfs below 3900 K, 0.8 for K-dwarfs, and 1.0 for G- and F-dwarfs — to discount planets whose atmospheres are most likely to have been eroded by extreme ultraviolet and X-ray flux. Visibility was modelled day by day against JWST's 85 to 135 degree solar elongation window from January 2026 through December 2027, yielding visibility days per year and the next open window for every target. A Mann-Whitney U test compared rocky-planet signal strength across host-star classes, and the output was a 22-page report with eight figures, a ranked top-30 target table, a two-year observing schedule, and 15 citations.
Data sources
- NASA Exoplanet Archive, composite planetary parameters table accessed December 2025 — 6,061 confirmed planets, 124 habitable zone candidates
- JWST operational pointing constraint — solar elongation window of 85 to 135 degrees, applied over January 2026 to December 2027
Limitations
The atmospheric retention model is a single penalty factor keyed only to stellar type, with no measured X-ray or ultraviolet flux, planetary magnetic field, or system age behind it, and the hypothesis test rests on just three non-M-dwarf rocky habitable zone planets. Rankings are also tied to the fixed 2026 to 2027 window, so targets excluded today may become observable in later cycles.
Figures from this analysis
How this research was produced
K-Dense Web planned and ran this astronomy investigation end to end — gathering the sources, carrying out the analysis, producing the figures, and drafting the report. The full session transcript, including every intermediate step, is available to view.
