Omega2 Cancri

For other star systems with this Bayer designation, see ω Cancri.

ω^2 Cancri

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Cancer
Right ascension	08^h 01^m 43.75679^s[1]
Declination	+25° 05′ 22.0823″[1]
Apparent magnitude (V)	6.32[2]
Characteristics
Evolutionary stage	main sequence[3]
Spectral type	A1 V[4]
B−V color index	0.023±0.006[2]
Astrometry
Radial velocity (Rv)	−7.6±2.5[5] km/s
Proper motion (μ)	RA: −25.112[1] mas/yr Dec.: +12.038[1] mas/yr
Parallax (π)	7.4046 ± 0.0486 mas[1]
Distance	440 ± 3 ly (135.1 ± 0.9 pc)
Absolute magnitude (MV)	0.51[2]
Details
Mass	2.59±0.06[3] M☉
Radius	2.5[6] R☉
Luminosity	68.0+8.3 −7.3[3] L☉
Temperature	9,354+174 −171[3] K
Rotational velocity (v sin i)	159[3] km/s
Other designations
ω^2 Cancri, 4 Cnc, BD+25°1816, HD 65856, HIP 39263, HR 3132, SAO 79869, CCDM J08017+2506A, WDS J08017+2505A, GSC 01930-00674[7]
Database references
SIMBAD	data

ω² Cancri is a star in the zodiac constellation Cancer, located around 810 light years away from the Sun. 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.^[2] 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.^[8]

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. It has 2.6^[3] times the mass of the Sun and about 2.5^[6] times the Sun's radius. The star is radiating 68^[3] times the Sun's luminosity from its photosphere at an effective temperature of 9354 K.^[3]

References

1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
2. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
3. Zorec, J.; et al. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy and Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
4. Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
5. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
6. Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics, 367 (Third ed.): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
7. "ome02 Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-02-23.
8. Schmidtke, P. C.; Africano, J. L. (2011), "KPNO Lunar Occultation Summary. III", The Astronomical Journal, 141 (1): 10, Bibcode:2011AJ....141...10S, doi:10.1088/0004-6256/141/1/10.