Editing Stellar classification (section)

===Class A=== <!-- if this section is renamed, please add {{anchor|Class A}}-->
{{See also|A-type main-sequence star}}
[[File:A5V star spectrum.png|thumb|Spectrum of a hypothetical A5V star]]
A-type stars are among the more common naked eye stars, and are white or bluish-white. They have strong hydrogen lines, at a maximum by A0, and also lines of ionized metals ([[iron|Fe]]&nbsp;II, [[magnesium|Mg]]&nbsp;II, [[silicon|Si]]&nbsp;II) at a maximum at A5. The presence of [[calcium|Ca]]&nbsp;II lines is notably strengthening by this point. About 1 in 160 (0.625%) of the main-sequence stars in the solar neighborhood are A-type stars,<ref group=lower-alpha name="proportions"/><ref name="LeDrew2001"/> which includes 9 stars within 15 parsecs.<ref>{{Cite web |title=THE 100 NEAREST STAR SYSTEMS |url=http://www.astro.gsu.edu/RECONS/TOP100.posted.htm |access-date=2022-04-13 |website=www.astro.gsu.edu}}</ref>

'''Example spectral standards:'''<ref name="Garrison"/>
* A0Van – [[Gamma Ursae Majoris]]
* A0Va – [[Vega]]
* A0Ib – [[Eta Leonis]]
* A0Ia – [[HD 21389]]
* A1V – [[Sirius|Sirius A]]
* A2Ia – [[Deneb]]
* A3Va – [[Fomalhaut]]