MU (μ) CEPHEI
RED SUPERGIANT STAR

Right Ascension:
21h 43m 30s

Best Seen:
6/1 - 2/15

Declination:
58º 46' 48"

Magnitude:
~ 4.0

Computer File:
mucep

Constellation:
Cepheus

Actual

Compared to Sun

Distance

~ 5300 l.y.

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Actual Brightness

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Surface Temperature

~ 5,400 ºF

~ 0.56

Diameter

~ 2.4 billion miles

~ 2700

Mass

--

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Surface Gravity

--

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Surface Composition (by mass)

74% hydrogen 24% helium 2% everything else

same

Spectral Type

M2 Iae

G2 V

Density (gram/cubic cm)

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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.

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.”

Item
Updated Notes

Coordinates 09-19-2003
checks with both SIMBAD and Hipparcos

Distance
09-19-2003
SIMBAD and Hipparcos give 0.62 mas parallax

Actual Brightness

Surface Temperature 09-19-2003
from The Flamsteed Collection, M stars range from 2400-3480 K; going with type M2, estimat temp at 3260 K

Diameter
09-19-2003
from http://www.aavso.org/vstar/vsots/1002.shtml

Mass

Surface Gravity

Surface Composition 09-12-2003
OK for all stars

Spectral Type
09-19-2003
SIMBAD and Hipparcos agree

Density –

Other Information
09-19-2003
variable info from aavso site (see diam) garnet star info from http://www.astro.uiuc.edu/~kaler/sow/garnet.html