Astrophysics (Index)About

pre-main-sequence star

(PMS, pre-MS, PMS object)
(star not yet with a nuclear reaction)

A pre-main-sequence star (PMS or pre-MS or PMS object) is a star in an early stage after being a protostar and before becoming a main sequence star, in other words, before its hydrogen burning. At this early point, the star's energy is from gravitational contraction. Some types:

Two distinctions used to classify pre-main-sequence stars and protostars are:

Active pre-main-sequence stars often emit X-rays and ultraviolet rays.

(star type,stellar evolution,protostars)
Further reading:

Referenced by pages:
convection zone
evolutionary track
FU Orionis star (FUor)
G-type star (G)
gravitational collapse
Hayashi track
HD 169142
Henyey track
Herbig AeBe star (HAeBe)
infrared excess (IRX)
K-type star (K)
main sequence star (MS)
PDS 70
spectral class
stellar evolution
T-Tauri star (TTS)
X-ray source
young stellar object (YSO)