25 Cancri is a common proper motion[4] star system in the zodiac constellation of Cancer, located around 148 light-years away from the Sun. It has the Bayer designation d2 Cancri (d2 Cnc); 25 Cancri (25 Cnc) is the Flamsteed designation. It is near the lower limit of visibility to the naked eye in good viewing conditions, appearing as a dim, yellow-white-hued star with a combined apparent visual magnitude of 6.11.[2] The pair have a relatively high proper motion, traversing the celestial sphere at an angular rate of 0.245″ per year.[9] It is moving further from the Earth with a heliocentric radial velocity of +38 km/s.[1]
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Cancer |
Right ascension | 08h 25m 49.87726s[1] |
Declination | +17° 02′ 46.5717″[1] |
Apparent magnitude (V) | 6.11[2] |
Characteristics | |
Spectral type | F6 V[3] |
B−V color index | 0.448±0.005[2] |
Astrometry | |
Radial velocity (Rv) | +37.56±0.13[1] km/s |
Proper motion (μ) | RA: −191.567[1] mas/yr Dec.: −151.554[1] mas/yr |
Parallax (π) | 21.9803 ± 0.0321 mas[1] |
Distance | 148.4 ± 0.2 ly (45.50 ± 0.07 pc) |
Absolute magnitude (MV) | 2.85[2] |
Details | |
25 Cnc A | |
Mass | 1.51[4] M☉ |
Radius | 2.0[1] R☉ |
Luminosity | 6.60[2] L☉ |
Surface gravity (log g) | 4.01[5] cgs |
Temperature | 6,487[5] K |
Metallicity [Fe/H] | −0.10[5] dex |
Rotational velocity (v sin i) | 37.74±0.55[6] km/s |
Age | 2.50[5] Gyr |
25 Cnc B | |
Mass | 0.34[4] M☉ |
Other designations | |
Database references | |
SIMBAD | data |
Based upon a stellar classification of F6 V,[3] the brighter component is an F-type main-sequence star that is generating energy through hydrogen fusion at its core. Cowley (1976) listed a class of F5 IIIm?,[10] which suggests it may be an Am star. However, this has not been confirmed.[6] It is about 2.5[5] billion years old with 1.51[4] times the mass of the Sun. The star is radiating 6.6[2] times the Sun's luminosity from its photosphere at an effective temperature of 6,487 K.[5]
The companion is 4.19 magnitudes fainter than the primary, and lies at an angular separation of 16.798″ along a position angle of 310°, as of 2013.[8] If the pair are gravitationally bound, then they orbit each other with a period of around 4.05 million years.[4]