Omicron² Cancri

Omicron² Cancri (ο² Cnc, ο² Cancri) is a solitary,[8] yellow-white hued star in the zodiac constellation of Cancer. With an apparent visual magnitude of +5.67,[2] it can be viewed with the naked eye on a dark night. Based upon an annual parallax shift of 21.68 mas as seen from Earth,[1] this star is located around 150 light years from the Sun. It most likely forms a co-moving pair with Omicron¹ Cancri.[9]

Omicron² Cancri

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Cancer
Right ascension	08^h 57^m 35.20006^s[1]
Declination	+15° 34′ 52.6145″[1]
Apparent magnitude (V)	+5.67[2]
Characteristics
Spectral type	F0 IV[3][4]
B−V color index	+0.204[2]
Astrometry
Proper motion (μ)	RA: +60.89[1] mas/yr Dec.: +19.57[1] mas/yr
Parallax (π)	21.68 ± 0.33[1] mas
Distance	150 ± 2 ly (46.1 ± 0.7 pc)
Absolute magnitude (MV)	+2.58[5]
Details[4]
Mass	1.72±0.01 M☉
Radius	1.62±0.08 R☉
Luminosity	10.30±0.43 L☉
Surface gravity (log g)	4.25 cgs
Temperature	7,868 K
Metallicity [Fe/H]	0.2 dex
Rotational velocity (v sin i)	90.5±4.5[5] km/s
Age	300[6] Myr
Other designations
ο^2 Cnc, 63 Cancri, BD+16° 1864, HD 76582, HIP 44001, HR 3565, SAO 98250[7]
Database references
SIMBAD	data

With a stellar classification of F0 IV,[3] this is an F-type subgiant star that has left the main sequence and is evolving toward the giant stage. It is estimated to be roughly 300[6] million years old with a relatively high rotation rate, as shown by a projected rotational velocity of around 90.5 km/s.[5] With 1.72 times the mass of the Sun and 1.62 times the Sun's radius, it is radiating 10.3 times the solar luminosity from its photosphere at an effective temperature of 7,868 K.[4]

The star has an infrared excess, suggesting it surrounded by a circumstellar debris disk.[6] Modelling of this structure indicates there are three distinct components, consisting of belts orbiting at distances of about 20 AU, 80 AU, and 270 AU from the central star. They are inclined at an angle of 64° to the line of sight along a position angle of 103°. The gaps between the belts are most likely maintained by orbiting planets.[4]

References

1. van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
2. Häggkvist, L.; Oja, T. (1966), "Photoelectric photometry of bright stars", Arkiv för Astronomi, 4: 137–163, Bibcode:1966ArA.....4..137H.
3. 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.
4. Marshall, Jonathan P.; et al. (July 2016), "Far-infrared and sub-millimetre imaging of HD 76582's circumstellar disc", Monthly Notices of the Royal Astronomical Society, 459 (3): 2893–2904, arXiv:1604.08306, Bibcode:2016MNRAS.459.2893M, doi:10.1093/mnras/stw813.
5. Reiners, A. (January 2006), "Rotation- and temperature-dependence of stellar latitudinal differential rotation", Astronomy and Astrophysics, 446 (1): 267–277, arXiv:astro-ph/0509399, Bibcode:2006A&A...446..267R, doi:10.1051/0004-6361:20053911.
6. Rhee, Joseph H.; et al. (May 2007), "Characterization of Dusty Debris Disks: The IRAS and Hipparcos Catalogs", The Astrophysical Journal, 660 (2): 1556–1571, arXiv:astro-ph/0609555, Bibcode:2007ApJ...660.1556R, doi:10.1086/509912.
7. "omi02 Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-06-14.
8. Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
9. Shaya, Ed J.; Olling, Rob P. (January 2011), "Very Wide Binaries and Other Comoving Stellar Companions: A Bayesian Analysis of the Hipparcos Catalogue", The Astrophysical Journal Supplement, 192 (1): 17, arXiv:1007.0425, Bibcode:2011ApJS..192....2S, doi:10.1088/0067-0049/192/1/2, 2.