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Mu (μ) Cephei

Red Supergiant Star

Right Ascension 21h 43m 30s Best Seen 6/1 - 2/15
Declination 58° 46' 48" Magnitude ~ 4.0
Constellation Cepheus
Actual Compared to Sun
Distance ~5300 ly --
Actual Brightness -- --
Surface Temperature ~5,400 °F ~0.56
Diameter ~2.4 billion miles ~ 2700
Mass -- --
Surface Gravity -- --
Surface Composition (by mass) 74% hydrogen
24% helium
2% everything else
same
Spectral Type M2 Iae G2 V
Density (gram/cubic cm) -- --

What To Look For Through The Telescope


  1. Recommended eyepiece: 24mm or 40 mm.

  2. When people look through the telescope a bright red or reddish-orange point of light should be seen.


Mu (μ) Cephei Information:


  1. This star is huge: if it were placed at our sun’s position, it would extend beyond the orbit of Saturn! (Saturn is ~10 AU from the sun)

  2. Like many other red giant stars, this is a variable star: its magnitude varies from 3.4 to 5.1. The period of the variation ranges between 730 and 4400 days.

  3. This star looks very red through the telescope. Sir William Herschel who discovered the planet Uranus) noticed this deep color, and it is often referred to as “Herschel’s Garnet Star.”

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References
Item Updated Notes
Coordinates 2003-09-19 checks with both SIMBAD and Hipparcos
Distance 2003-09-19 SIMBAD and Hipparcos give 0.62 mas parallax
Actual Brightness --
Surface Temperature 2003-09-19 from The Flamsteed Collection, M stars range from 2400-3480 K; going with type M2, estimat temp at 3260 K
Diameter 2003-09-19 from http://www.aavso.org/vstar/vsots/1002.shtml
Mass --
Surface Gravity --
Surface Composition 2003-09-12 OK for all stars
Spectral Type 2003-09-19 SIMBAD and Hipparcos agree
Density -–
Other Information 2003-09-19 variable info from aavso site (see diam) garnet star info from http://www.astro.uiuc.edu/~kaler/sow/garnet.html