14 Ceti

14 Ceti is a single[11] star in the equatorial constellation of Cetus. It is faintly visible to the naked eye under good viewing conditions, having an apparent visual magnitude of 5.84.[2] The distance to 14 Ceti can be estimated from its annual parallax shift of 17.26″,[1] which puts it 189 light years away. It is moving further from the Earth with a heliocentric radial velocity of +11 km/s,[7] having recently come no closer than 178 ly.[6]

14 Ceti
Observation data
Epoch J2000      Equinox J2000
Constellation Cetus
Right ascension 00h 35m 32.83354s[1]
Declination −00° 30′ 20.1981″[1]
Apparent magnitude (V) 5.84[2]
Characteristics
Evolutionary stage Hertzsprung gap[3]
Spectral type F5 V[4][5] or F5 IV[2]
B−V color index 0.444±0.006[6]
Astrometry
Radial velocity (Rv)+11.3±0.2[7] km/s
Proper motion (μ) RA: +143.043[1] mas/yr
Dec.: −62.326[1] mas/yr
Parallax (π)17.2643 ± 0.0606[1] mas
Distance188.9 ± 0.7 ly
(57.9 ± 0.2 pc)
Absolute magnitude (MV)2.26±0.04[8]
Details
Mass1.55±0.1[2] M☉
Radius2.6[2] R☉
Luminosity10.7[2] L☉
Surface gravity (log g)3.87±0.15[9] cgs
Temperature6,583±90[9] K
Metallicity [Fe/H]−0.11±0.06[9] dex
Rotational velocity (v sin i)5[2] km/s
Age2.1±0.4[9] Gyr
Other designations
14 Cet, BD−01° 68, FK5 2036, GC 701, HD 3229, HIP 2787, HR 143, SAO 128843[10]
Database references
SIMBADdata

Gray (1989) as well as Houk and Swift (1999) have this star classified as an F-type main-sequence star with a stellar classification of F5 V.[4][5] However, in the 5th revised edition of the Bright Star Catalogue it was classed by Hoffleit and Warren (1991) as a more evolved subgiant star with a class of F5 IV.[12] The absolute magnitude and effective temperature for this star shows that it is entering the Hertzsprung gap, which is occupied by a class of stars that have consumed the hydrogen at their core but have not yet begun hydrogen fusion along a shell surrounding the center.[11]

Evolutionary models for this star give an estimated age of around 2.1[9] billion years with 1.6[2] times the mass of the Sun. It has 2.6[2] times the Sun's radius and is radiating 10.7[2] times the Sun's luminosity from its photosphere at an effective temperature of about 6,583 K.[9] There is a thin convective envelope near its surface.[2] The star has a lower abundance of elements more massive than helium – what astronomers' term the metallicity – compared to the Sun.[9] The projected rotational velocity is a relatively low 5 km/s, but the rotation rate is unknown since the axial tilt hasn't been determined.[2]

14 Ceti shows an X-ray emission of 0.33×1030 erg s−1, which is on the high side for an F5 star. Both the corona and chromosphere of this star show indications of a magnetic field, and a surface field was detected in 2009 with a strength of −30 G. This made it the only known star between classes F0 and F7 to have a Zeeman effect detected. Two possible explanations for this field are that it is a fast rotator with a dynamo-driven field, or that it is a former Ap star.[11] The activity properties of this star make it more likely to be the latter.[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.
  2. Aurière, M.; et al. (February 2015), "The magnetic fields at the surface of active single G-K giants", Astronomy & Astrophysics, 574: 30, arXiv:1411.6230, Bibcode:2015A&A...574A..90A, doi:10.1051/0004-6361/201424579, A90.
  3. Aurière, M.; et al. (November 2014), "Descendants of magnetic and non-magnetic A-type stars", in Mathys, G.; Griffin, E.; Kochukhov, O.; Monier, R.; Wahlgren, G. (eds.), Putting A Stars into Context: Evolution, Environment, and Related Stars, Proceedings of the international conference held on June 3-7, 2013 at Moscow M.V. Lomonosov State University in Moscow, Russia, Moscow: Pero, pp. 444–450, arXiv:1310.6942, Bibcode:2014psce.conf..444A.
  4. Gray, R. O. (1989), "The extension of the MK spectral classification system to the intermediate population II F type stars", Astronomical Journal, 98 (3): 1049–1062, Bibcode:1989AJ.....98.1049G, doi:10.1086/115195.
  5. Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey, Ann Arbor, Michigan: Department of Astronomy, University of Michigan, 5, Bibcode:1999MSS...C05....0H.
  6. 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.
  7. Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065.
  8. Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191.
  9. Bensby, T.; et al. (2014), "Exploring the Milky Way stellar disk. A detailed elemental abundance study of 714 F and G dwarf stars in the solar neighbourhood", Astronomy & Astrophysics, 562 (A71): 28, arXiv:1309.2631, Bibcode:2014A&A...562A..71B, doi:10.1051/0004-6361/201322631.
  10. "14 Cet". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved December 20, 2018.
  11. Aurière, M.; et al. (July 2012), "14 Ceti: a probable Ap-star-descendant entering the Hertzsprung gap", Astronomy & Astrophysics, 543: 6, arXiv:1205.6962, Bibcode:2012A&A...543A.118A, doi:10.1051/0004-6361/201219324, A118.
  12. Hoffleit, D.; Warren, W. H., Jr. (November 1995), Bright Star Catalogue (5th Revised ed.), Bibcode:1995yCat.5050....0H.
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