main sequence

noun

, Astronomy.

1. a narrow band in the Hertzsprung-Russell diagram in which 90 percent of all observed stars are plotted.

main sequence

noun

1. astronomy
   1. a diagonal band on the Hertzsprung Russell diagram containing about 90% of all known stars; stars evolve onto and then off the band during their lifetime
   2. ( as modifier )

      a main-sequence star

main sequence

/ mān /

1. The continuous, generally diagonal line or band in the Hertzsprung-Russell diagram ranging from the upper left to the lower right and representing stars of average size whose luminosities correspond predictably to their surface temperatures. Stars in this grouping maintain a stable nuclear reaction and experience only small fluctuations in luminosity and temperature. Main-sequence stars are believed to be in the stable, middle phase of their development; they are expected to move off the main sequence once the hydrogen in their core is exhausted. At that point, depending on its size, a main-sequence star will become a giant star, a supergiant star, or a white dwarf. The more massive the star, the faster it burns its nuclear fuel and the shorter it remains in the main sequence.
2. See more at Hertzsprung-Russell diagram

Word History and Origins

Origin of main sequence¹

First recorded in 1925–30

Example Sentences

Because whatever its shortcomings, it was the first planet ever discovered outside our own solar system orbiting a main sequence star like the sun.

From Time

Returning to Room X in the main sequence we find wood-carving and pottery.

From Project Gutenberg

This control, termed the Sequence Break System, allows concurrent operation of several in-out devices and the main sequence.

From Project Gutenberg

The main sequence of noise out of which the peaks rise is the 21-centimeter hydrogen line.

From Project Gutenberg

The main sequence, however, is constant and is that illustrated in fig. 13.

From Project Gutenberg