Stellar classification - Wikipedia, the free encyclopedia
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In astronomy, stellar classification is a classification of stars based on its spectral characteristics. The spectral class of a star, is a designation of a class to a star describing the ionizati...
en.wikipedia.org/wiki/Stellar_classification
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Spectral Class Intrinsic Color Temperature (K) Prominent Absorption Lines ... The spectra of O-Type stars shows the presence of hydrogen and helium. At these temperatures most of the hydrogen is ionized, so the hydrogen lines are weak. Both HeI and HeII (singly ionized helium) are seen in the higher temperature examples.
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hyperphysics.phy-astr.gsu.edu/Hbase/starlog/staspe.html
hyperphysics.phy-astr.gsu.edu/Hbase/starlog/staspe.html
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If you saw a cloud whose spectrum showed no hydrogen lines, how would you tell if it were hot or cool? For a cloud of pure hydrogen, you couldn't. But for real stars, which contain atoms of many elements besides hydrogen, you could look at the absorption and emission lines of other elements ... Spectral Types...
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cas.sdss.org/dr7/en/proj/advanced/spectraltypes/lines.a...
cas.sdss.org/dr7/en/proj/advanced/spectraltypes/lines.asp
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for example, the stars in the spectral type known as class B are blue-white, and are referred to as helium stars because the dominant lines in their spectra are the lines in helium spectra. ... Class A has the strongest hydrogen lines, B is characterized principally by neutral helium (with weaker hydrogen), and O by...
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www.answers.com/topic/spectral-type
www.answers.com/topic/spectral-type
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1. The hydrogen lines in spectral type A stars; * a. are most narrow for supergiants. b. are most narrow for main sequence stars. c. can not be used to estimate the luminosity of the star. d. are very weak and difficult to see.
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www.claycomb2002.com/Chapter8Qa.pdf
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It also shows the positions of some of the more important absorption lines to use in spectral typing. Check the lines in the order below to decide the spectral type. ... Stars hotter than A0 (i.e. O and B type stars) have few lines other than the hydrogen lines and the peak of the black body curve is at short wavelength.
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voyager2.dvc.edu/~kcastle/comparison%20spectra/How%20To...
voyager2.dvc.edu/~kcastle/comparison%20spectra/How%20To%20Do%20Spectral%20Classification.pdf
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O-type stars are massive, bright, hot stars. They are the bluest of the of the main sequence stars. ... Their spectra exhibit rather weak hydrogen lines, atomic helium, and also ionised helium (HeII – helium atoms which have lost one electron). This is the only main sequence spectral type in which ionised helium can be seen;
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www.peripatus.gen.nz/Astronomy/SpeTypO.html
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This site is intended for students age 14 and up, and for anyone interested in learning about our universe. ... The Life Cycle of Stars Booklet ... However, these types of supernovae were originally classified based on the existence of hydrogen spectral lines: Type Ia do not show hydrogen lines, while Type II do.
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imagine.gsfc.nasa.gov/docs/science/know_l2/supernovae.h...
imagine.gsfc.nasa.gov/docs/science/know_l2/supernovae.html
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SAO/NASA ADS Astronomy Abstract Service ... Title:; Hydrogen Line Contours in Stars of Early Spectral Type. ... Find Similar Abstracts:
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adsabs.harvard.edu/abs/1964PhDT.........1S
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