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Eta Cephei
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Star Eta Cephei

Subgiant Eta Cephei is located 47 light years away from the Sun. It is a single star of spectral class K0IV, that has 160 % of solar mass. There is at least one exoplanet in this system.
Sun distance
47 light years
galaxy map

Eta Cephei

Subgiant, High proper motion star
Spectral class: K0IV

Location +

Ascension iconRight ascension: 20h 45m 17.572s
Declination iconDeclination: 61° 50' 32.709'' (northern hemisphere)
Parallax iconParallax: 69.598
Distance iconSun distance: 46.863 ly | 14.4 pc
Star position
The position of a star tells us where it appears in the sky, similar to how we use coordinates like latitude and longitude on Earth. In astronomy, the three main coordinates are right ascension, declination and distance. .. icon More about Star position in StellarGuide

Basic characteristic

icon weight
Mass: 160 % M Sun
| 1676 M Jupiter
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Star mass
Mass of the star Eta Cephei is 1.6 solar masses.

The mass of a star is the total amount of matter it contains. It is one of the most important properties of a star, as it determines almost everything about how the star lives, changes, and dies. In astronomy, star mass is usually measured in solar masses (M☉) — where 1 solar mass is equal to the mass of our Sun... icon More about Star mass in StellarGuide
radius icon
Size: 412 % R Sun
| 41 R Jupiter
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Star size
Radius of the star Eta Cephei is 4.12 solar radii.

The size of a star refers to its radius — the distance from its center to its surface. Star size is usually measured in solar radii (R☉), where 1 solar radius equals approximately 696,000 kilometers. Depending on their type and life stage, stars can be much smaller or larger than the Sun... icon More about Star size in StellarGuide
temperature icon
Temperature: 4950 K | 0.86 T Sun
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Star temperature
Surface temperature of Eta Cephei is 4950 K, which is 86 % of the temperature on the surface of the Sun.

The temperature of a star refers to the temperature at its surface, also called the photosphere. It is measured in kelvins (K), the standard unit for temperature in astronomy. A star’s temperature tells us a lot about its physical properties and where it stands in its evolutionary stage... icon More about Star temperature in StellarGuide
time icon
Age: 2.5 billions years | 0.54 Sun
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Star age
Star Eta Cephei is 2.5 billion years old, which is about 0.54 of the Sun's age.

The age of a star tells us how long it has been shining since it formed. Knowing a star’s age helps astronomers understand its life stage, how it has changed over time, and what will happen to it in the future... icon More about Star age in StellarGuide
luminosity icon
Luminosity: 9.7 L Sun
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Star luminosity
Luminosity is the total amount of energy a star gives off every second. Think of it as the star’s true brightness — not just how bright it looks from Earth. This is important because some stars may appear dim simply because they are far away, not because they’re actually faint... icon More about Star luminosity in StellarGuide

Photometry

Magnitude iconApparent magnitude (V): 3.4
Magnitude iconAbsolute magnitude (V): 2.6
Absolute stellar magnitude in different parts of the electromagnetic spectrum from infrared (K band) to ultraviolet (U band).
5
10
15
20
25
30
35
K
2.1
H
1.6
J
1.2
Grp
0.8
I
0.8
G
0.6
V
0.5
Gbp
0.5
B
0.4
U
0.3

Eta Cephei system structure

 Eta Cephei
Eta Cephei b
unconfirmed
 0.64 AU 203.5 M⊕ 163.6 days
More about Eta Cephei
Nearby star Eta Cephei is is approximately 4 times bigger than the Sun and temperature on its surface is around 4950 K (4677 °C), which is about 86 % of Sun's temperature.
       Eta Cephei can be found in northern celestial hemisphere, and it is possible to see it with naked eye. The star is easily observable from Northern America, Europe and Asia.
Other designations of this star
eta Cep, 3 Cephei, BD+61 2050, FK5 783, HD 198149, HIP 102422, HR 7957, SAO 19019, Gaia EDR3 2195115561168483712
External sources
simbad icon
Simbad database (* eta Cep)
Astronomical database SIMBAD (the Set of Identifications, Measurements and Bibliography for Astronomical Data)
gaia icon
Gaia database (Gaia EDR3 2195115561168483712)
Archive from the Gaia mission
Class of stars Subgiant
A subgiant is a term used to describe a luminous star that is typically running out of hydrogen for nuclear fusion and is thus departing from the main sequence. These stars are classified as Yerkes luminosity class IV.
Closest stars

 Alpha Cephei
 2 M☉ 4 ly

G 230-42
 - 5.4 ly

Wolf 1084
 - 8.7 ly

G 264-12
 - 8.9 ly

Wolf 1130
 - 10.8 ly
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