!"#$%&$'()*+%,'-&"./0#/

12 3(-0+/'+(-&$#'433'1215'1265'721862 9-:"&(#"$;'2 ?()-,%*(&'#;&$@/#"#'433'72>8'

72 ?@($(:/$0"+'%&A'#)/+$0(#+()"+'0/A#@"B#'433'7278

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• L&$/M0%,'#(-0+/'+(-&$#• !"N/0/&*%,'#(-0+/'+(-&$#• O-+,"A/%&'#(-0+/'+(-&$#P• Q,I/0#')%0%A(R'''

6

dN/dS ∝ S−5/2

S%,%R;'A/"*/#

•

• H@/'&-:I/0'A/"$;'"#'$@/&P'

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• L&M0/A"/&$#– a:(-&$'(

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11

3$/,,%0'#)/+$0%'L'• O stars are the hottest, with temperatures from about 20,000K up to more than

100,000K. These stars have few absorption lines, generally due to helium. These stars burn out in a few million years.

• B stars have temperatures between about 10,000 and 20,000K. They are noticeably blue.

• A stars have strong absorption lines of Hydrogen. Temperatures are about 8000-10,000K. They appear white.

• F stars are slightly hotter than the Sun. Absorption lines of metals appear • G stars have temperatures between 5000 and 6000K. They appear yellow. Our

Sun is a G star and lives for 10 Gyr • K stars appear orange. Temperatures are 3000-5000K. • M stars are the coolest stars. They are so cool (2000-3000K) that molecules,

including water, carbon monoxide, Vanadium Oxide and Titanium oxide are visible.

16

Ages ≈10 Gyr

(M/M⊙)3info: http://www.astro.sunysb.edu/fwalter/AST101/spt.html

L&"*%,':%##'

dN/dm ∝ m−2.35 M⊙

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