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JWST Measures the Most Distant Known Ultra-Cold Y Dwarf
A two-year NIRCam baseline places JADES-GS-BD-5 about 64 parsecs away, roughly three times farther than prior parallax-measured Y dwarfs.
Summary
A two-year NIRCam baseline places JADES-GS-BD-5 about 64 parsecs away, roughly three times farther than prior parallax-measured Y dwarfs.
The team measures 49.8 milliarcseconds per year of proper motion and a parallax of 15.7 milliarcseconds, yielding a geometric distance of 64 parsecs with stated uncertainty of plus six and minus five. Its inferred motion fits the Galactic thin disk, while its faint luminosity and near-infrared spectrum place it beyond Y1 and among the coldest dwarfs known. Evolution models put it in the planetary-mass regime, though current atmosphere models do not reproduce the full spectral-energy distribution.
Why it matters
A two-year NIRCam baseline places JADES-GS-BD-5 about 64 parsecs away, roughly three times farther than prior parallax-measured Y dwarfs.
Limits and context
- Evolution models put it in the planetary-mass regime, though current atmosphere models do not reproduce the full spectral-energy distribution.
Key claims
A two-year NIRCam baseline places JADES-GS-BD-5 about 64 parsecs away, roughly three times farther than prior parallax-measured Y dwarfs.
Qualification: Evolution models put it in the planetary-mass regime, though current atmosphere models do not reproduce the full spectral-energy distribution.
Evidence: source-2026-11-06-015
Sources
- arXiv preprint 2611.08346, original v1arXiv · primary research
Corrections
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