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Topic: Spectral class

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	Spectral class - Wikipedia, the free encyclopedia
		In astronomy one method of classifying stars is through the analysis of their absorption spectra, by this method stars are assigned a spectral class.
		Since the absorption spectra is dependent on the surface temperature of the star the spectral class gives an indications of the temperature of the star.
		The current system of naming spectral class was adopted in 1910 and consists of a letter and a number from 0 to 9, for example the spectral class of the sun is G2.
	en.wikipedia.org /wiki/Spectral_class (158 words)

	Stellar classification - Wikipedia, the free encyclopedia
		Class O stars are very hot and very luminous, being bluish in colour; in fact, most of their output is in the ultraviolet range.
		Class W is subdivided into subclasses WN and WC according to the dominance of nitrogen or carbon in their spectra (and outer layers).
		Class R and N stars are carbon stars (red giants thought to reach the end of their life) which run parallel to the normal classification system from roughly mid G to late M. These have more recently been remapped into a unified carbon classifier C, with N0 starting at roughly C6.
	www.wikipedia.org /wiki/Stellar_classification (2249 words)

	Stellar classification - Wikipedia, the free encyclopedia
		Class L stars contain lithium which is rapidly destroyed in hotter stars.
		The Yerkes spectral classification, also called the MKK system from the authors' initials, is a system of stellar spectral classification introduced in 1943 by William Wilson Morgan, Phillip C. Keenan and Edith Kellman of Yerkes Observatory.
		This classification is based on spectral lines sensitive to stellar surface gravity which is related to luminosity, as opposed to the Harvard classification which is based on surface temperature.
	en.wikipedia.org /wiki/Stellar_classification (2249 words)

	spectral class articles on Encyclopedia.com (Site not responding. Last check: 2007-10-21)
		A bluish-white giant (spectral class B2 II) with apparent magnitude 1.5, it is one of the 25 brightest stars in the sky.
		An orange giant star (spectral class K5 III) with apparent magnitude averaging 0.85, it is one of the 20 brightest stars in the sky.
		An orange giant of spectral class K0 III, it is the nearest giant star, lying at a distance of 35 light-years.
	www.encyclopedia.com /articles/12196.html (451 words)

	spectral class on Encyclopedia.com (Site not responding. Last check: 2007-10-21)
		SPECTRAL CLASS [spectral class] in astronomy, a classification of the stars by their spectrum and luminosity.
		Thus, a B0 is the hottest B-type star, B5 is halfway between types B and A, and B9 is only slightly hotter than type A. The table entitled Spectral Classes for Main Sequence Stars gives the characteristics of the seven principal types.
		Spectral Sensitivity of Vision and Bioluminescence in the Midwater Shrimp Sergestes similis.
	www.encyclopedia.com /html/s1/spectral.asp (525 words)

	Stellar classification : Spectral class
		Spectral characteristics offer a way to classify stars which gives information about temperature in a different way - particular absorption lines can be observed only for a certain range of temperatures because only in that range are the involved atomic energy levels populated.
		Class G stars are probably the most well known for only the reason that our Sun is of this class.
		The Yerkes spectral classification, also called the MKK system, is a system of stellar spectral classification introduced in 1943 by William W. Morgen[?], Phillip C. Keenan[?] and Edith Kellman[?] of Yerkes Observatory.
	www.fastload.org /sp/Spectral_class.html (1373 words)

	GIS Land Cover 1999-2000 Information, Illinois Department of Agriculture
		Spectral signatures were extracted from each TM/ETM+ triplicate data set utilizing an Isodata K-means clustering procedure (Duda and Hart 1973) and experimentation indicated that 200-250 spectral classes should be derived for each data set.
		The labeling and reduction of the spectral classes from the unsupervised classification procedures into the final information classes (water, wetland, etc.) was accomplished by photo-interpretation of NAPP 3 aerial photography.
		Spectral class #6 represents Peoria Lake, Upper Peoria Lake, and a portion of the mainstem of the Illinois River.
	www.agr.state.il.us /gis/landcover99-00.html (1756 words)

	Spectra
		It was noted very early that the spectral sequence in this form correlates with color, ranging from a blue tint for O and B stars to reddish for class M. Since color depends on surface temperature, so must the spectral class.
		Decimal subdivisions of the spectral classes go toward lower temperature, for example, A0 lies at the hot end of class A near a temperature of 10,000 K, while A9 is at the cool end near 7200 K. The Sun, with a temperature of 5800 K, is class G2.
		R and N are now lumped together under class "C" for "carbon." The exception to the "giant-star rule" is a rare class of main-sequence carbon stars that have been contaminated by evolving companions.
	www.astro.uiuc.edu /~kaler/sow/spectra.html (5857 words)

	Spatially Defined and Spectrally Homogeneous Field Samples From Remote Sensing Data (Site not responding. Last check: 2007-10-21)
		Spectral map derived from Band-3 was used as the reference for the different forest types.
		Spectral map derived from the Band-1 was used as the reference for the dry dipterocarp forest and the agricultural areas.
		Spectral map derived from the Band-2 was used as the reference for the agriculture area.
	www.icimod.org /focus/gis/spectral_abstract.html (1817 words)

	Spectral classification of late-type dwarfs
		In practice, a spectral classification system is defined by a number of stars (or brown dwarfs) which are selected as fiducial standards, each representing a particular spectral class (M1, M2, M3, etc.).
		A spectral classification system tied to physical parameters must change with each revision of the theoretical models, and a changing system makes it very difficult to establish the readily-understood common reference system which is essential for spectral types to be of any use.
		Spectral class M is characterised by the presence of strong absorption bands due to the diatomic molecule titanium oxide, TiO (Morgan, Keenan \& Kellman, 1943).
	www-int.stsci.edu /~inr/ldwarf.html (2629 words)

	Stars
		With one known exception, class L is a mixture of low mass dwarfs and brown dwarfs, while T stars are all
		Carbon stars, class C, for which carbon exceeds oxygen in abundance, and class S, for which they are about equal, are listed at the end of the main table.
		MKK class, which consists of its decimalized letter class (in which the broad classes are subdivided 0 [zero] through 9 from warmest to coolest) followed by a Roman numeral that gives the luminosity: I through V for supergiant, bright giant, giant, subgiant, and dwarf.
	www.astro.uiuc.edu /~kaler/sow/class.html (554 words)

	eSky: Spectral Classification
		The classification of stars according to their spectra; each major spectral classification is given a letter, with additional numbers providing further subdivisions.
		A star's full spectral classification often also includes a 'luminosity class', a Roman numeral from I to VII indicating the star's luminosity, which correlates with its mass.
		Dwarfs: a very numerous class of main sequence stars, whose mass and luminosity is generally comparable with that of the Sun.
	www.glyphweb.com /esky/concepts/spectralclassification.html (1065 words)

	442_unsup_class_lab
		The classes that result from unsupervised classification are referred to as spectral classes.
		Because they are based on natural groupings of the image values, the identity of the spectral classes will not be initially known.
		are, this spectral class seems to include roads and other features in the urban and suburban area.
	www.ac.wwu.edu /~wallin/envr442/442_unsup_class_lab_ERDAS.html (4996 words)

	Spectral analysis of sub-mJy radio sources (Site not responding. Last check: 2007-10-21)
		The number of spectra by spectral class are given in Table 5.1.
		Composite redshift-corrected spectra of classes (A), (B) and (C) are shown in Figures 5.1, 5.2 and 5.3, providing an example of the features prominent in these classes.
		The galaxies are marked by the spectral class (A, B, C or D) to which they have been assigned.
	www.atnf.csiro.au /people/ahopkins/thesis/node9.html (3556 words)

	The Webfooted Astronomer: Secrets of the Harvard Classification Revealed
		Strong spectral lines of hydrogen begin to appear a B0 and increase in strength as the spectral class reaches B9.
		Spectral lines due to hydrogen begin to weaken, the K line of calcium continues to get stronger, and characteristic spectral lines (neutral and ionized) of such as Fe, Mn, and Na begin to appear.
		R and N stars are sometimes combined into one class: C. Stars of class S exhibit complex spectra containing bright hydrogen lines and molecular bands due to zirconium oxide.
	www.seattleastro.org /webfoot/feb00/pg2.htm (767 words)

	Spectral Classes
		The variations in spectral lines for different stars are due primarily to the difference in temperature of the outer layers of gas in the star.
		This is an historical artefact as classes were assigned to spectra before the underlying physical relationship was known.
		Each spectral class is thus broken down into ten subdivisions so that, for example, an F2 star is hotter than an F7 star.
	outreach.atnf.csiro.au /education/senior/astrophysics/spectral_class.html (1079 words)

	Astronomy glossary: radio galaxy, red shift, resolving power, singularity, solar wind, spectral class : Etacude.com
		spectral class - Star classification scheme which based on the stellar spectral lines.
		Notice that each main spectral class (represented by the alphabets O, B, A, F, G, K and M) can be subdivided into ten smaller gradations which are indicated as numbers, in the order of increasing temperature, from 0 to 9.
		For example K0 is the hottest in the spectral class K and K5 is slightly cooler, at a temperature around 4000°C. The Sun is classified as a G2 star, corresponds to a temperature of about 5500°C. Copyright
	sciencepark.etacude.com /astronomy/basic4.php (495 words)

	Red Comparison Stars Policy (Site not responding. Last check: 2007-10-21)
		Consequently, it would seem that unless it is a main sequence dwarf, red stars of spectral class M0 or later are unsafe to use as comparison stars.
		Since the vast majority of bright red stars are giants and not dwarfs, and considering that visual observers have different spectral responses (particularly with red stars), it would be sensible to avoid using stars of spectral class M0 or later as comparison stars in the future.
		As accurate spectral data on stars is not always readily available, it is proposed that a limit is imposed, instead, on the basis of the star's B-V index.
	www.britastro.org /vss/redcomps.html (361 words)

	Spectral class - Memory Alpha
		In simplest terms, the spectral class of a star is a measurement of its color and temperature.
		Example: A star of class B0 would be hotter than a class B7 star, which in turn would be hotter than a A3-class star.
		A white dwarf's spectral class always starts with the letter D (for "degenerate mass").
	www.memory-alpha.org /en/index.php/Spectral_class (277 words)

	Spectral class: Facts and details from Encyclopedia Topic (Site not responding. Last check: 2007-10-21)
		[Follow this hyperlink for a summary of this subject] the term spectral class refers to classifying objects according to their spectral line spectral line quick summary:
		A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range,...
		In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequenly...
	www.absoluteastronomy.com /encyclopedia/s/sp/spectral_class.htm (560 words)

	OSSERVATORIO G.V. SCHIAPARELLI - SEZIONE COMETE
		Picture 5 shows the intensity of the lines produced by particular ions as a function of temperature (or spectral class, that is almost the same).
		The spectral classification that is used nowadays is a refinement, proposed in 1943 by Morgan, Keenan, Kellman (and thus sometimes indicated as MKK) of the original Cannon classes.
		For a same temperature (and thus for the same spectral class) it is possible to find stars of a very different brightness.
	www.astrogeo.va.it /astronom/spettri/teoriaen.htm (2557 words)

	Spectral class (Site not responding. Last check: 2007-10-21)
		In astronomy the term spectral class refers to classifying objects according to their spectral line s, which indicate an object's chemical composition.
		: The class of 1982 was particularly noteworthy.
		A fastening device is disclosed which consists of a first portion that may be made as an integral part of an object such as small electronic devices, tools or cup holders and other items, or may be separately fastened thereto; and a second portion that may be made as an...
	www.serebella.com /encyclopedia/article-Spectral_class.html (1296 words)

	SearchEngine.net - Spectral Class Star
		Each spectral class is defined by the spectrum of a standard star against which the other stars are compared.
		Summary: A new spectral class of stars, L Dwarfs, has been defined that extends the previously-defined spectral classes of normal stars to
		Spectral lines are formed in the photosphere of a star so we must understand the...
	www.searchengine.net /Spectral_Class_Star.htm (206 words)

	[No title] (Site not responding. Last check: 2007-10-21)
		Spectral Diagnostics Inc.("Spectral") (TSE: SDI) and Elan Corporation, plc ("Elan") (NYSE: ELN) today reported the successful completion of the MEDIC clinical trial carried out by Sepsis Inc. (a majority owned subsidiary of Spectral focused on the development of diagnostic tests for infection).
		Spectral Diagnostics Inc. (TSE-SDI), developers of the Cardiac STATus(TM) line of Rapid Panel Tests including the three- marker Cardiac Panel(TM) and Controls, reported today its financial results for the second quarter ended September 30, 1999.
		Spectral Diagnostics Inc. (TSE-SDI), developers of the Cardiac STATus(TM) line of rapid format cardiac diagnostic panel test kits including the three- marker Cardiac Panel(TM) and Controls, reported today its financial results for the fiscal year ended March 31, 1999.
	www.acor.org /drugs/pipeline/companies/news/2715.news (756 words)

	[No title] (Site not responding. Last check: 2007-10-21)
		Spectral's arrays generate a genome wide molecular profile and quantification of chromosomal imbalances on a single chip.
		Spectral Genomics' platform technology enables users to markedly increase the signal sensitivity, specificity, reproducibility, and utility of Genomic microarrays at a lower cost.
		Contrary to the modification of the surface by chemicals like poly-L-lysine or silane to attach unmodified DNA, Spectral Genomics' core technology is based on a unique proprietary chemical coupling of DNA fragments to untreated surfaces.
	www.acor.org /drugs/pipeline/news/parsed/7322415.news (391 words)

	late star concept from the Astronomy knowledge base (Site not responding. Last check: 2007-10-21)
		G star (19 kinds, 195 facts) - Spectral type for yellow stars., Yellowish star in which the H and K lines of Ca II have become dominant and in which a tremendous profusion of spectral lines of both neutral and ionized metals, particularly iron, begins to show.
		M star (12 kinds, 105 facts) - Spectral type for red stars, such as Betelgeuse, Antares, and Proxima Centauri., Star of spectral type M are cool red stars with surface temperatures of less than 3600 K whose spectra are dominated by molecular bands, especially those of TiO.
		S star (1 kind, 8 facts) - Red-giant stars of spectral type S are similar to M stars except that the dominant oxides are those of the metals of the fifth period (Zr, Y, etc.) instead of the third (Ti, Sc, V).
	www.site.uottawa.ca:4321 /astronomy/latestar.html (911 words)

	The Spectral Sequence as a Temperature Sequence (Site not responding. Last check: 2007-10-21)
		We now know that the different spectral types are primarily a consequence of different surface temperatures for the stars, with composition differences playing only a minor role.
		For example, a dominant characteristic of spectral class A stars is the presence of strong hydrogen lines, but ionized helium lines are only present in the class O stars.
		On the other hand, spectral lines associated with molecules are only found for spectral classes K and M. This is because these correspond to low surface temperatures, and molecules can only hold together in stars with relatively low surface temperatures.
	csep10.phys.utk.edu /astr162/lect/stars/spectra.html (397 words)

	Assignment #2
		The spectral classes are given along the top of the form.
		The spectral class of a star is a measure of the surface temperature of a star.
		The Spectral class for Rigel Kentaurus is G2 V. The G is the overall spectral type while the "2" means that Rigel Kentaurus falls ~20 % of the way between G and K. The Roman Numeral "V" is the Luminosity class of the star.
	zebu.uoregon.edu /~imamura/122/exercises/hw2.html (289 words)

	Ionized Calcium (Site not responding. Last check: 2007-10-21)
		You were actually looking at the spectral lines of calcium that has been ionized two times.
		The hottest stars are in the O spectral class, the coolest are M class stars.
		Spectral classes have been remembered for many years by the mnemonic Oh Be A Fine Girl (or Guy) Kiss Me.
	curie.uncg.edu /~nmmurray/light/cal.html (241 words)

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