Population II

English

Alternative forms

• population II

Etymology

Proposed by astronomer Walter Baade in 1944.

Proper noun

Population II

1. (astrophysics, usually attributively) A population or group of stars formed early in the history of the Universe, characterized by having a low metallicity.

   Coordinate terms: Population I, Population III

   • 2019 December 11, Brian Koberlein, “The Stars In Our Galaxy Are More Varied Than We Thought”, in Forbes‎^[1], archived from the original on 2022-09-15:

     While the thick disk is largely composed of Population II stars, they found it contains two stellar populations.

   • 2021 May 21, Tom Metcalfe, “An ancient star casts new light on the birth of the universe”, in NBC News‎^[2], archived from the original on 2022-07-06:

     Those heavy elements were created by fusion within Population II stars that exploded as supernovas and seeded them into interstellar clouds.

   • 2022 December 6, Jonathan O'Callaghan, “Astronomers Grapple with JWST’s Discovery of Early Galaxies”, in Scientific American‎^[3], archived from the original on 2022-12-09:

     The brightness of these galaxies could be attributed to such stars, which would be much hotter and brighter than subsequent Population II stars and Population I stars, such as our sun, both of which fill our modern-day universe.

Derived terms

• Pop II (abbreviation)