5 Cancri
Star in the constellation Cancer
From Wikipedia, the free encyclopedia
5 Cancri is a single[9] star in the zodiac constellation of Cancer, located around 520 light years away from the Sun. It is just visible to the naked eye under good seeing conditions as a dim, blue-white hued star with an apparent visual magnitude of 5.99.[2] This object is moving closer to the Sun with a heliocentric radial velocity of −10 km/s.[5]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cancer |
| Right ascension | 08h 01m 30.28830s[1] |
| Declination | +16° 27′ 19.1191″[1] |
| Apparent magnitude (V) | 5.99[2] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | B9.5 Vn[4] |
| B−V color index | −0.024±0.003[2] |
| Astrometry | |
| Radial velocity (Rv) | −10.0±1.5[5] km/s |
| Proper motion (μ) | RA: +4.12[6] mas/yr Dec.: −5.43[6] mas/yr |
| Parallax (π) | 6.2251±0.1419 mas[1] |
| Distance | 520 ± 10 ly (161 ± 4 pc) |
| Absolute magnitude (MV) | −0.09[2] |
| Details | |
| Mass | 2.93±0.10[3] M☉ |
| Radius | 3.1[7] R☉ |
| Luminosity | 121.1+20.2 −17.3[3] L☉ |
| Surface gravity (log g) | 4.5[4] cgs |
| Temperature | 9,727+90 −89[3] K |
| Rotational velocity (v sin i) | 188[3] km/s |
| Age | 36[4] Myr |
| Other designations | |
| 5 Cnc, BD+16°1612, HD 65873, HIP 39236, HR 3134, SAO 97485[8] | |
| Database references | |
| SIMBAD | data |
At one point this was thought to be a spectroscopic binary system. It is a Be star with a weak circumstellar disk of gas that has around three times the radius of the host star.[10] The stellar classification of 5 Cancri is B9.5 Vn,[4] matching a B-type main-sequence star with "nebulous" lines due to rapid rotation. It is 36[4] million years old with a high projected rotational velocity of 188 km/s.[3] The star has 2.9[3] times the mass of the Sun and about 3.1[7] times the Sun's radius. It is radiating 121[3] times the Sun's luminosity from its photosphere at an effective temperature of 9,727 K.[3]
