Astrophysics (Index)About

Lyman alpha

(Ly-α, Lyα)
(first line in the Lyman series)

Lyman alpha (Ly-α or Lyα) is a hydrogen spectral line, the first line in the Lyman series and is a target of interest for astronomical observation. It has a wavelength of 121.6 nm, in the extreme ultraviolet (EUV) range (as is the whole Lyman series) and cannot be observed from the ground unless considerably redshifted. Among its uses is as a sign of star formation at long distances.

The term Lyman alpha also applies to corresponding lines of any ion with just one electron. For 4He and deuterium, the wavelength is less than 1 nm different than that of 1H.

Further reading:
121.6nm2.5PHz10eVLyman alpha

Referenced by pages:
Dark Energy Spectroscopic Instrument (DESI)
damped Lyman alpha absorber (DLA)
electron orbital
Gunn-Peterson trough
intensity mapping
Lyman-alpha emitter (LAE)
Lunar Reconnaissance Orbiter (LRO)
Lyman-alpha forest
Lyman series (L)
N 103B
oscillator strength
spectral line designation
star formation (SF)
transit spectroscopy