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

An international research team led by Kristina Kislyakova, Senior Scientist at the Department of Astrophysics of the University of Vienna, has detected for the first time the X-ray emission from the astrospheres around three sun-like stars, so called main sequence stars which are stars in the prime of their life, and has thus recorded such winds for the first time directly, allowing them to place constraints on the mass loss rate of the stars via their stellar winds.

From Science Daily

They result from the explosive pairing between a normal type of star — for example, a main sequence furnace like Earth’s sun or an elephantine red giant — and a white dwarf, a smoldering stellar core left behind after a star’s demise.

From New York Times

Wolf-Rayets rise above and beyond the diagram's “main sequence,” where ordinary stars congregate.

From Scientific American

In this case, astronomers tried to look for the planet's host star, and were surprised to discover that its starlight was not bright enough to constitute an ordinary, main sequence star.

From Salon

The initial discovery of a planet around a main sequence star - those that fuse hydrogen into helium within their cores - was made in 1995 by astronomers Didier Queloz and Michel Mayor.

From BBC