Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Cancer |
Right ascension | 08h 32m 42.49600s[1] |
Declination | 20° 26′ 28.1865″[1] |
Apparent magnitude (V) | 5.34[2] |
Characteristics | |
Spectral type | K3 III[2] |
U−B color index | +1.40[2] |
B−V color index | +1.25[2] |
Astrometry | |
Radial velocity (Rv) | +22.46[3] km/s |
Proper motion (μ) | RA: −46.33[1] mas/yr Dec.: −44.31[1] mas/yr |
Parallax (π) | 10.93 ± 0.40 mas[1] |
Distance | 300 ± 10 ly (91 ± 3 pc) |
Absolute magnitude (MV) | +0.44[4] |
Details | |
Mass | 1.51[5] M☉ |
Radius | 17[6] R☉ |
Luminosity | 87[5] L☉ |
Surface gravity (log g) | 2.1[6] cgs |
Temperature | 4,415±57[5] K |
Metallicity [Fe/H] | 0.07±0.21[4] dex |
Rotational velocity (v sin i) | 2.7[6] km/s |
Age | 3.92[5] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Eta Cancri, Latinized from η Cancri, is a single,[8] orange-hued star in the zodiac constellation of Cancer. It is a faint star but visible to the naked eye with an apparent visual magnitude of 5.34.[2] The annual parallax shift of 10.93[1] mas as seen from Earth yields a distance estimate of 155 light years from the Sun. It is moving further away with a radial velocity of +22 km/s.[3]
A stellar classification of K3 III[2] for Eta Cancri indicates that, at the estimated age of 3.9 billion years old,[5] it has left the main sequence and become an evolved giant star. The spectrum shows unusually strong absorption lines of cyanogen.[2] It has 1.5[5] times the mass of the Sun and has expanded to 17[6] times the Sun's radius. The star is radiating 87[5] times the Sun's luminosity from its photosphere at an effective temperature of around 4,415 K.[5]
In Chinese astronomy, Ghost (Chinese: 鬼宿; pinyin: Guǐ Xiù) refers to an asterism consisting of Theta Cancri, Eta Cancri, Gamma Cancri and Delta Cancri.[9] Eta Cancri itself is the second star of Ghost (Chinese: 鬼宿二; pinyin: Guǐ Xiù èr), following the designation from its determinative star (θ Cnc) from east to west.