Astrophysics (Index)About

calcium

(Ca)
(element, Ca, atomic number 20)

Calcium (Ca) is the element with atomic number 20, symbol Ca. Its most common isotope has mass number 40, but 42, 43, and 44 are more stable and 46 is stable as well. It is the fifth most common element in the Earth's crust. Calcium is commonly detected in stars, F-type star and G-type star showing ionized calcium, e.g., the Sun, which (among the Fraunhofer lines) has strong absorption lines of singly ionized calcium (Ca II), including the (Fraunhofer) H line (396.85 nm) and K line (393.37 nm). K-type stars and M-type stars often show neutral calcium (Ca I).


(element,metal,chemistry)
Further reading:
https://en.wikipedia.org/wiki/Calcium
https://en.wikipedia.org/wiki/Calcium_triplet
http://hyperphysics.phy-astr.gsu.edu/hbase/pertab/ca.html
https://www.rsc.org/periodic-table/element/20/calcium
https://physics.nist.gov/PhysRefData/Handbook/Tables/calciumtable2.htm

Referenced by pages:
alpha element
Am star
CAI
calcium-rich gap transient (ca-rich gap transient)
carbonate-silicate cycle
cosmic dust
element
Fraunhofer lines
Herbig AeBe star (HAeBe)
K-line
Lick Observatory Calcium Line Survey (LkCl)
rare designator prefixes
T-Tauri star (TTS)
Type Ia supernova
Wilson-Bappu effect

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