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M-Type Star

(M)
(type of star with a temperature in the vicinity of 2500K)

An M-Type Star is of the M-Class, a Spectral Class for cool stars including Red Dwarves (M Dwarves) which are Main Sequence Stars, and Red Giants, which are beyond the main sequence. The common element is the Temperature, which is less than other main sequence stars. They all have very weak Hydrogen Absorption Lines.

Some red dwarfs are Proxima Centauri, Barnard's Star, Lacaille 9352, Lalande 21185, Ross 154, Ross 248, Wolf 359, and Gliese 581.

Characteristics:

Redconventional color
2000-3700KSurface Temperature
.96-1.15radius
<.45mass
8-20Absolute Magnitude(visual)
0.08-0.6Luminosity(bolometric)
1-10 trillion yearsmain-sequence lifetime
76.45%abundance

Some characteristics of M Dwarfs (Mass, Radius and Luminosity as fraction of the Solar values):

ClassMassRadiusLuminosityTemp(K)
M0.6.62.0723800"Early"
M1.49.49.0353600
M2.44.44.0233400
M3.36.39.0153250
M4.20.26.00553100
M5.14.20.00222800"Mid"
M6.10.15.00092600
M7.09.12.00052500
M8.08.11.00032400
M9.075.08.000152300"Late"

These classes are often followed by a V, e.g., M7V, indicating a main sequence (dwarf, as in non-giant) star.

An example red giant is Betelgeuse. The red giant phase lasts on the order of a billion years. Their absolute Magnitude is brighter because of their size.


(star type,spectral type)
http://en.wikipedia.org/wiki/Stellar_classification

Referenced by:
Bcool
Brown Dwarf (BD)
Calcium (Ca)
K2
K-Type Star (K)
L-Type Star (L)
M Dwarf
Solar Mass (MSun)
Orion
Red Dwarf
Red Giant
Scholz's Star
Spectral Class
Transiting Exoplanet Survey Satellite (TESS)
Ultracool Dwarf
Wilson-Bappu Effect

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