27 Cancri is a single[8] star in the zodiac constellation of Cancer, located around 990 light-years away from the Sun.[1] It is visible to the naked eye as a faint, red-hued star with a typical apparent visual magnitude of around +5.56.[2] The star is moving closer to the Earth with a heliocentric radial velocity of −8.3 km/s.[5] It is a member of the Arcturus stream, a group of stars with high proper motion and metal-poor properties thought to be the remnants of a small galaxy consumed by the Milky Way.[9]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cancer |
| Right ascension | 08h 26m 43.94035s[1] |
| Declination | +12° 39′ 16.6066″[1] |
| Apparent magnitude (V) | +5.56[2] |
| Characteristics | |
| Evolutionary stage | Asymptotic giant branch[3] |
| Spectral type | M3 IIIa[4] |
| B−V color index | 1.608±0.002[2] |
| Variable type | SRb[3] |
| Astrometry | |
| Radial velocity (Rv) | −8.30±0.31[5] km/s |
| Proper motion (μ) | RA: −19.760[1] mas/yr Dec.: −104.664[1] mas/yr |
| Parallax (π) | 3.3094 ± 0.3176 mas[1] |
| Distance | 990 ± 90 ly (300 ± 30 pc) |
| Absolute magnitude (MV) | −1.62[2] |
| Details | |
| Radius | 119[1] R☉ |
| Luminosity | 2,455+707 −550[6] L☉ |
| Surface gravity (log g) | 1.00[6] cgs |
| Temperature | 3,574[6] K |
| Metallicity [Fe/H] | 0.00[6] dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an aging red giant with a stellar classification of M3 IIIa,[4] currently on the asymptotic giant branch.[3] It is classified as a semiregular variable star of type SRb and its brightness varies from magnitude +5.41 to +5.75 with a period of 40 days.[10] The star is radiating around 2,455[6] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,574 K.[6]