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Erakis

Garnet Star, Herschel’s Garnet Star, Mu Cephei

Proper NamesErakis, Garnet Star, Herschel’s Garnet Star, Mu Cephei
Bayer DesignationMu Cephei
Flamsteed NumberNone
HR (BSC)8316
HD206936
ConstellationCepheus
Right Ascension21h 43m 30s
Declination+58° 46' 48"
Distancec.3,100 light years
c.900 parsecs
(highly uncertain)*
MagnitudeApparent: +4.01
Absolute: -5.86
Spectral ClassM2-Ia red supergiant or hypergiant
Optimum VisibilityAugust / September (Usually visible from northern latitudes)

Deep red Erakis shines out from the northern clouds of the Elephant's Trunk Nebula, IC 1396 in southern Cepheus. Within the nebula is a broad open cluster of stars, Trumpler 37 or Collinder 439, and Erakis is sometimes listed as being a member of, or at least associated with, this cluster. Imagery provided by Aladin sky atlas


* Erakis is a very distant star, and because of this, its parallax angle of just 0.1190 milli-arcseconds is too small to extrapolate a reliable value for its distance. Ignoring other considerations, this parallax figure would yield a distance of more than 27,000 light years, but this result is too extreme to be realistic. Using other methods to calculate the star's distance, the most likely results converge on a value of a little more than three thousand light years, though there is considerable margin for error in this result. Other calculation methods suggest that Erakis may be closer than this to the Sun, perhaps by a matter of several hundred light years.

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