η Cephei (eta Cephei)

η Cephei is a double hypergiant star in the constellation of Cepheus.

η Cephei visual magnitude is 3.43. Because of its moderate brightness, η Cephei should be easily visible from locations with dark skyes, while it can be barely visible, or not visible at all, from skyes affected by light pollution.

The table below summarizes the key facts about η Cephei:

Color of η Cephei ⬤

Magnitude of η Cephei 3.43

Class Hypergiant

VISIBILITY RIGHT NOW η Cephei (eta Cephei) is above the horizon from Greenwich, United Kingdom [change]. Altitude: 57°.

Celestial coordinates and finder chart of η Cephei

η Cephei is situated close to the northern celestial pole and, as such, it is visible for most part of the year from the northern hemisphere. Celestial coordinates for the J2000 equinox as well as galactic coordinates of η Cephei are provided in the following table:

Right Ascension J2000 20h 45m 17s

Declination J2000 +61° 50’ 20”

Galactic Longitude 97.86°

Galactic Latitude 11.64°

Constellation Cepheus

The simplified sky map below shows the position of η Cephei in the sky:

Simplified finder chart for η Cephei (eta Cephei).

Visibility of η Cephei from your location

Location: Greenwich, United Kingdom [change]
Latitude: 51° 28’ 47” N
Longitude: 0° 00’ 00” E
Timezone: Europe/London

η Cephei (eta Cephei) is circumpolar and transits at 08:19 UTC (altitude: 79.6°)

Digitized Sky Survey image of η Cephei

The image below is a photograph of η Cephei from the Digitized Sky Survey 2 (DSS2 - see the credits section) taken in the red channel. The area of sky represented in the image is 0.5x0.5 degrees (30x30 arcmins). The proper motion of η Cephei is 0.087 arcsec per year in Right Ascension and 0.818 arcsec per year in Declination and the associated displacement for the next 1000 years is represented with the red arrow.

DSS2 image of η Cephei. The red arrow shows the motion of η Cephei during the next 1000 years (1.45 arcmin in Right Ascension and 13.63 arcmin in declination);

Distance of η Cephei from the Sun and relative movement

η Cephei is distant 46.75 light years from the Sun and it is moving towards the Sun at the speed of 87 kilometers per second.

Distance (parsec) 14.34 pc

Distance (light year) 46.75 ly

Heliocentric radial velocity -87 km/s

Proper Motion RA 0.087 arcsec/year

Proper Motion Dec 0.818 arcsec/year

Spectral properties of η Cephei

η Cephei belongs to spectral class K0 and has a luminosity class of IV corresponding to a hypergiant star.

Absolute magnitude 2.65

Spectral Type K0IV

Color Index (B-V) 0.92

Temperature of η Cephei 4943K

The red dot in the diagram below shows where η Cephei is situated in the Hertzsprung–Russell diagram.

H-R diagram showing the position of η Cephei. Attribution: Richard Powell / CC BY-SA

η Cephei star system properties

η Cephei is a visual double star which can be observed only with the help of very large telescopes. The table below shows key information about the η Cephei double sysyem:

Main star magnitude 3.43

Secondary star magnitude 11.63

Magnitude difference 8.2

Separation 51.7 arcsec

Alternative designations of η Cephei

Bayer designation η Cephei
(eta Cephei)

Flamsteed designation 3 Cephei

Henry Draper Catalogue HD198149

SAO Catalogue SAO19019

Hipparcos Catalogue HIP102422

Durchmusterung Catalogue BD+61 2050

Gliese Catalogue Gl 807

FK5 Catalogue 783

Aitken Double Star Catalogue ADS14276

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Other stars in Cepheus