Xi Cancri
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cancer |
| Right ascension | 09h 09m 21.541s[1] |
| Declination | +22° 02′ 43.58″[1] |
| Apparent magnitude (V) | +5.15[2] (5.70 + 6.20)[3] |
| Characteristics | |
| Spectral type | G9 III Fe-1 CH-0.5[4] |
| U−B color index | +0.75[2] |
| B−V color index | +0.96[2] |
| Astrometry | |
| Radial velocity (Rv) | +7.7±0.3[5] km/s |
| Proper motion (μ) | RA: −3.147 mas/yr[1] Dec.: 9.159 mas/yr[1] |
| Parallax (π) | 8.004±0.3286 mas[1] |
| Distance | 410 ± 20 ly (125 ± 5 pc) |
| Absolute magnitude (MV) | −0.12[4] |
| Orbit[6][7] | |
| Period (P) | 1,700.76 ± 2.7 d (4.6564 ± 0.0074 yr) |
| Semi-major axis (a) | 0.0105±0.0017[3]" (≥ 103.0×106 km (0.689 AU)) |
| Eccentricity (e) | 0.06±0.05 |
| Periastron epoch (T) | 2428876.86±10.0 JD |
| Argument of periastron (ω) (secondary) | 301.1±38.3° |
| Semi-amplitude (K1) (primary) | 4.41±0.02 km/s |
| Details | |
| Mass | 3.40+0.11 −0.21[1] M☉ |
| Radius | 16.13+0.73 −0.66[1] R☉ |
| Luminosity | 149+12 −11[1] L☉ |
| Surface gravity (log g) | 2.62±0.07[1] cgs |
| Temperature | 5,025+9 −11[1] K |
| Rotational velocity (v sin i) | 2.1±1.0[8] km/s |
| Age | 271+54 −63[1] Myr |
| Other designations | |
| Nahn, ξ Cnc, 77 Cancri, BD+22°2061, FK5 1239, GC 12635, HD 78515, HIP 44946, HR 3627, SAO 80666, WDS J09094+2203AB[9] | |
| Database references | |
| SIMBAD | data |
Xi Cancri is a binary star system in the zodiac constellation of Cancer. Its name is a Bayer designation that is Latinised from ξ Cancri, and abbreviated Xi Cnc or ξ Cnc. This system is faintly visible to the naked eye with a combined apparent visual magnitude of +5.15.[2] Based upon parallax measurements,[1] it is approximately 410 light-years distant from the Sun. At its present distance, the visual magnitude is diminished by an extinction factor of 0.135 due to interstellar dust.[3] It is drifting further away with a line of sight velocity of +8 km/s.[5]
The two components are designated Xi Cancri A (formally named Nahn, pronounced /ˈnɑːn/)[10] and B. The primary component is an evolved giant star. The position of this system near the ecliptic means it is subject to lunar occultation.[11]
Nomenclature
[edit]ξ Cancri (Latinised to Xi Cancri) is the system's Bayer designation. The designations of the two components as Xi Cancri A and B derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[12]
Xi Cancri together with Lambda Leonis (Alterf) were the Persian Nahn, "the Nose", and the Coptic Piautos, "the Eye", both lunar asterisms.[13] Nahn was also the name given to Xi Cancri in a 1971 NASA technical memorandum.[14] In 2016, the IAU organized a Working Group on Star Names (WGSN)[15] to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[16] It approved the name Nahn for the component Xi Cancri A on 1 June 2018 and it is now so included in the List of IAU-approved Star Names.[10]
Properties
[edit]The variable radial velocity of this system was discovered by W. W. Campbell in 1922.[7] Xi Cancri is a single-lined spectroscopic binary star system with an orbital period of 4.66 years, an eccentricity of 0.06, and a semimajor axis of 0.01 arcsecond.
The primary, Xi Cancri A, is a yellow G-type giant with a stellar classification of G9 III Fe-1 CH-0.5 and an apparent magnitude of +5.70. The suffix notation indicates the spectrum displays underabundances of iron and cyanide compared to similar stars. An evolved star that has exhausted the supply of hydrogen at its core, it is 271 million years old with 3.4 times the mass of the Sun and has expanded to 16 times the Sun's radius. The star is radiating 149 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 5,025 K.[1] Its companion, Xi Cancri B, is of magnitude 6.20.[3]
References
[edit]- ^ a b c d e f g h i j k l Vallenari, A.; et al. (Gaia collaboration) (2023), "Gaia Data Release 3. Summary of the content and survey properties", Astronomy and Astrophysics, 674: A1, arXiv:2208.00211, Bibcode:2023A&A...674A...1G, doi:10.1051/0004-6361/202243940, S2CID 244398875 Gaia DR3 record for this source at VizieR.
- ^ a b c d Sturch, C. R.; Helfer, H. L. (November 1972), "UBVRI photometry of north galactic pole K giants. II", Astronomical Journal, 77: 726, Bibcode:1972AJ.....77..726S, doi:10.1086/111344.
- ^ a b c d Malkov, O. Yu.; et al. (2012), "Dynamical masses of a selected sample of orbital binaries", Astronomy & Astrophysics, 546: A69, Bibcode:2012A&A...546A..69M, doi:10.1051/0004-6361/201219774.
- ^ a b 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 XHIP record for this object at VizieR.
- ^ a b 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.
- ^ Pourbaix, D.; et al. (2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy & Astrophysics, 424 (2): 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213, S2CID 119387088.
- ^ a b Jackson, E. S.; et al. (May 1957), "The Orbits of the Spectroscopic Binaries Omicron Tauri, Xi Cancri, and Mu Ursae Majories", Astrophysical Journal, 125: 712, Bibcode:1957ApJ...125..712J, doi:10.1086/146345.
- ^ Glebocki, R.; Gnacinski, P. (2005), "Catalog of Stellar Rotational Velocities", VizieR On-line Data Catalog: III/244. Originally Published in: 2005csss...13..571G; 2005yCat.3244....0G, 3244, Bibcode:2005yCat.3244....0G.
- ^ "ksi Cnc", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2017-06-15.
- ^ a b Naming Stars, IAU.org, archived from the original on 11 April 2020, retrieved 18 June 2018.
- ^ Herr, Richard B. (April 1969), "Identification List of Spectroscopic and Eclipsing Binaries Subject to Occultations by the Moon", Publications of the Astronomical Society of the Pacific, 81 (479): 105, Bibcode:1969PASP...81..105H, doi:10.1086/128748.
- ^ Hessman, F. V.; et al. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
- ^ Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc., p. 114, ISBN 0-486-21079-0, retrieved 2010-12-12.
{{citation}}: CS1 maint: ignored ISBN errors (link) - ^ Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, Jet Propulsion Laboratory, California Institute of Technology, retrieved 2025-06-26.
- ^ IAU Working Group on Star Names (WGSN), International Astronomical Union, archived from the original on 10 June 2016, retrieved 22 May 2016.
- ^ WG Triennial Report (2015–2018) – Star Names (PDF), International Astronomical Union, p. 5, archived from the original (PDF) on 2022-10-09, retrieved 2018-07-14.
