Fr.: trajet évolutif
In a theoretical → Hertzsprung-Russell diagram, the path taken by an evolving star.
Fr.: trajet de Hayashi
The path on the → Hertzsprung-Russell diagram that is followed by a fully → convective → pre-main sequence star to reach the → zero-age main sequence. Hayashi tracks for → low-mass stars are near vertical. At higher masses, stars become increasingly radiative as they contract and the Hayashi tracks are almost horizontal.
Named after the Japanese astrophysicist Chushiro Hayashi (1920-2010), who published his paper in 1961 (PASJ 13, 450); → track.
Fr.: trajet de Henyey
A nearly horizontal path on the → Hertzsprung-Russell diagram that a → pre-main sequence star of small mass follows in an early stage of evolution after leaving the → Hayashi track and before reaching the → main sequence. During this stage the pre-main sequence star remains almost wholly in radiative equilibrium.
After Louis George Henyey (1910-1970), American astronomer. Henyey et al. (1955, PASP 67, 154).
1) tor; 2) tor gereftan
Fr.: 1) trace, piste, trajet; 2) suivre la trace de
1a) Evidence, as a mark or a series of marks, that something has passed.
M.E. trak, from M.Fr. trac, from O.Fr. trac "track of horses, trace" (mid-15c.), possibly from a Germanic source (compare M.L.G. treck, Du. trek "drawing, pulling).
Tor, from Lori, Laki, Fini, Bandar-Abâsi tor "track, trace, mark;"
maybe ultimately from Proto-Ir. *tar- "to cross over;" cf. Av. tar-
"to cross over;" Mid.Pers. (+*ui-) widur-, widôr- "to pass (beyond, over); Pers.
gozar; Baluci tar(r)- "to walk;" Yaghnobi tir-, ter-
"to go, leave;" → trans-.
The facility that allows a telescope to follow a celestial object during in its westward motion in the sky.
Verbal noun from → track.
Fr.: précision de poursuite
The accuracy with which a → telescope tracks a target.
white dwarf cooling track
râh-e sardeš-e sefid kutulé
Fr.: trajet de refroidissement de naine blanche
In the → Hertzsprung-Russell diagram, the evolutionary track followed by a → low-mass or an → intermediate-mass star when it can no longer produce thermonuclear energy. The track starts at the end of the → horizontal branch to lead the star to a → white dwarf phase.