Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso

Z (Astrophysics)

Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_1702-4

Definition

In astrophysics, Z is used to denote the mass fraction of all elements except hydrogen and helium in a star or other astronomical object. Those elements, considered as “heavy elements” and often called “metals” by astronomers, differ with respect to hydrogen and helium because their production implies processing by a star, either through nuclear reactions during the Main Sequence or giant phase or as a consequence of a supernova explosive event at the end of the star’s life. The abundance of these heavy elements is thus a very important indicator of the processing by stars in a galaxy.

In contrast, lower case z is used by astronomers to denote the redshift of a (typically) distant object moving away from the observer.

See Also

Keywords

Mass Fraction Bioorganic Chemistry Nuclear Reaction Important Indicator Heavy Element 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.LESIAObservatoire Paris-Site de MeudonMeudonFrance