Astronomy:25 Canum Venaticorum
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Canes Venatici |
| Right ascension | 13h 37m 27.62782s[1] |
| Declination | +36° 17′ 41.6337″[1] |
| Apparent magnitude (V) | +4.82[2] (4.98 + 6.95)[3] |
| Characteristics | |
| Spectral type | A7 III + A8 V:[4] |
| Astrometry | |
| Radial velocity (Rv) | −10.4±2.1[2] km/s |
| Proper motion (μ) | RA: −95.54[1] mas/yr Dec.: +23.75[1] mas/yr |
| Parallax (π) | 16.42 ± 0.53[1] mas |
| Distance | 199 ± 6 ly (61 ± 2 pc) |
| Absolute magnitude (MV) | 0.90[2] |
| Orbit[5] | |
| Period (P) | 228 yr |
| Semi-major axis (a) | 1.02″ |
| Eccentricity (e) | 0.80 |
| Inclination (i) | 147° |
| Longitude of the node (Ω) | 87° |
| Periastron epoch (T) | 1864.0 |
| Argument of periastron (ω) (secondary) | 159° |
| Details | |
| 25 CVn A | |
| Mass | 2.23[6] M☉ |
| Surface gravity (log g) | 3.85[7] cgs |
| Temperature | 7,609±259[7] K |
| Rotational velocity (v sin i) | 235[8] km/s |
| Age | 659[7] Myr |
| 25 CVn B | |
| Mass | 1.58[6] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
25 Canum Venaticorum, also named Jordanus,[10] is a binary star[11] system in the northern constellation of Canes Venatici, approximately 199[1] light years from the Sun. It is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of +4.82[2] The system is moving closer to the Earth with a heliocentric radial velocity of roughly −10 km/s.[2]
This is a wide binary system with an orbital period of 228 years and an eccentricity of 0.80.[5] As of 2001, they had a projected separation of 107.0 astronomical unit|AU.[6] The magnitude 4.98[3] primary, component A, has a stellar classification of A7 III,[4] which matches an A-type giant star. It is 659[7] million years old with a projected rotational velocity of 235 km/s. This rate of spin is giving the star an oblate shape with an equatorial bulge that is an estimated 27% larger than the polar radius.[8] The companion, component B, is a magnitude 6.95[3] A-type main-sequence star with a class of A8 V:.[4] The ':' suffix indicates some uncertainty in the classification of this star.
This star was part of Jordanus, a former constellation representing the Jordan River. The IAU Working Group on Star Names approved the name Jordanus for 25 Canum Venaticorum A on 17 September 2026.[10]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 2.4 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 3.2 Mason, B. D. et al. (December 2001), "The Washington Visual Double Star Catalog (WDS), Version 2019-01-21", The Astronomical Journal (U. S. Naval Observatory, Washington D.C.) 122 (6): 3466–3471, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M.
- ↑ 4.0 4.1 4.2 Stephenson, C. B.; Sanwal, N. B. (June 1969), "The masses of stars above the main sequence", Astronomical Journal 74: 689–704, doi:10.1086/110845, Bibcode: 1969AJ.....74..689S.
- ↑ 5.0 5.1 Söderhjelm, Staffan (1999), "Visual binary orbits and masses POST HIPPARCOS", Astronomy and Astrophysics 341: 121–140, Bibcode: 1999A&A...341..121S.
- ↑ 6.0 6.1 6.2 De Rosa, R. J.; Patience, J.; Wilson, P. A.; Schneider, A.; Wiktorowicz, S. J.; Vigan, A.; Marois, C.; Song, I. et al. (2014), "The VAST Survey - III. The multiplicity of A-type stars within 75 pc", Monthly Notices of the Royal Astronomical Society 437 (2): 1216–1240, doi:10.1093/mnras/stt1932, Bibcode: 2014MNRAS.437.1216D.
- ↑ 7.0 7.1 7.2 7.3 David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal 804 (2): 146, doi:10.1088/0004-637X/804/2/146, Bibcode: 2015ApJ...804..146D.
- ↑ 8.0 8.1 van Belle, Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review 20 (1), doi:10.1007/s00159-012-0051-2, Bibcode: 2012A&ARv..20...51V.
- ↑ "25 CVn". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=25+CVn.
- ↑ 10.0 10.1 "IAU Catalog of Star Names". https://exopla.net/star-names/modern-iau-star-names/.
- ↑ Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
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