Omega2 Cancri
White-hued star in the constellation Cancer
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ω2 Cancri is a star in the zodiac constellation Cancer. It has the Flamsteed designation 4 Cancri; ω2 Cancri is the Bayer designation, which is Latinised to omega2 Cancri and abbreviated to ω2 Cnc or omega2 Cnc. The star is near the lower limit of visibility to the naked eye, having an apparent visual magnitude of 6.32.[1] Based on parallax measurements, it is located around 432 light-years (133 pc) away from the Sun. It is moving closer to the Earth with a heliocentric radial velocity of −8 km/s.[5] The position of this star near the ecliptic means it is subject to lunar occultations.[7]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cancer[1] |
| Right ascension | 08h 01m 43.757s[2] |
| Declination | +25° 05′ 22.08″[2] |
| Apparent magnitude (V) | 6.32[1] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | A1 V[4] |
| B−V color index | 0.023±0.006[1] |
| Astrometry | |
| Radial velocity (Rv) | −7.6±2.5[5] km/s |
| Proper motion (μ) | RA: −25.138 mas/yr[2] Dec.: +12.276 mas/yr[2] |
| Parallax (π) | 7.5434±0.0393 mas[2] |
| Distance | 432 ± 2 ly (132.6 ± 0.7 pc) |
| Absolute magnitude (MV) | 0.51[1] |
| Details | |
| Mass | 2.59±0.06[3] M☉ |
| Radius | 2.55±0.02[2] R☉ |
| Luminosity | 68.0+8.3 −7.3[3] L☉ |
| Surface gravity (log g) | 3.886±0.006[2] cgs |
| Temperature | 9,354+174 −171[3] K |
| Rotational velocity (v sin i) | 159[3] km/s |
| Age | 506±75[2] Myr |
| Other designations | |
| ω2 Cancri, 4 Cnc, BD+25°1816, HD 65856, HIP 39263, HR 3132, SAO 79869, CCDM J08017+2506A, WDS J08017+2505A, GSC 01930-00674[6] | |
| Database references | |
| SIMBAD | data |
This is an ordinary A-type main-sequence star with a stellar classification of A1 V,[4] which indicates it is generating energy through hydrogen fusion at its core. At an estimated age of approximately 500[2] million years, it is spinning rapidly with a projected rotational velocity of 159 km/s.[3] It has 2.6[3] times the mass of the Sun and about 2.55 times the Sun's radius.[2] The star is radiating 68[3] times the Sun's luminosity from its photosphere at an effective temperature of 9,354 K.[3]