HD 111968, also known by the Bayer designation n Centauri, is a single[8] star in the southern constellation of Centaurus. It is a white-hued star that is faintly visible to the naked eye with an apparent visual magnitude of +4.25.[2] The star is located at a distance of approximately 149 light years from the Sun based on parallax.[1] The radial velocity of the star is poorly constrained, with an estimated value of 2.5 km/s.[2]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 12h 53m 26.20s[1] |
| Declination | −40° 10′ 43.9″[1] |
| Apparent magnitude (V) | +4.25[2] |
| Characteristics | |
| Spectral type | A7IV[3] or A7V[4] |
| B−V color index | +0.224±0.014[2] |
| Astrometry | |
| Proper motion (μ) | RA: +70.84±0.14[1] mas/yr Dec.: −22.54±0.10[1] mas/yr |
| Parallax (π) | 21.95 ± 0.19 mas[1] |
| Distance | 149 ± 1 ly (45.6 ± 0.4 pc) |
| Absolute magnitude (MV) | +0.86[5] |
| Details | |
| Mass | 1.62[6] M☉ |
| Luminosity | 34.34[2] L☉ |
| Surface gravity (log g) | 3.87±0.14[6] cgs |
| Temperature | 7,835±266[6] K |
| Rotational velocity (v sin i) | 92.4±4.6[5] km/s |
| Age | 401[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is classified as an A-type star but there has been disagreement about the luminosity class. A. de Vaucouleurs in 1957 found a class of III, suggesting this is an evolved giant star.[9] O. J. Eggen gave a class of V in 1962,[10] as did R. O. Gray and R. F. Garrison in 1989,[4] indicating this is a main sequence star. In 1979, N. Houk found a class of IV,[3] meaning this is a subgiant star.
HD 111968 is a young star, some 400 million years old, with 1.6 times the mass of the Sun.[6] It is spinning with a projected rotational velocity of 92 km/s.[5] The star is radiating 34[2] times the luminosity of the Sun from its photosphere at an effective temperature of 7,835 K.[6]
References
edit- ^ a b c d e f 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, S2CID 18759600. Vizier catalog entry
- ^ a b c d e f 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.
- ^ a b Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 3, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1982mcts.book.....H.
- ^ a b Gray, R. O.; Garrison, R. F. (1989), "The Late A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation", The Astrophysical Journal Supplement Series, 70: 623, Bibcode:1989ApJS...70..623G, doi:10.1086/191349.
- ^ a b c Ammler-von Eiff, Matthias; Reiners, Ansgar (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics, 542: A116, arXiv:1204.2459, Bibcode:2012A&A...542A.116A, doi:10.1051/0004-6361/201118724, S2CID 53666672.
- ^ a b c d e f 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, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
- ^ "n Cen". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-10-01.
- ^ 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, S2CID 14878976.
- ^ de Vaucouleurs, A. (1957). "Spectral types and luminosities of B, A and F southern stars". Monthly Notices of the Royal Astronomical Society. 117 (4): 449. Bibcode:1957MNRAS.117..449D. doi:10.1093/mnras/117.4.449.
- ^ Eggen, O. J. (1962), "Space-velocity vectors for 3483 stars with proper motion and radial velocity", Royal Observatory Bulletin, 51: 79, Bibcode:1962RGOB...51...79E.