HD 2454
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Pisces |
| Right ascension | 00h 28m 20.042s[1] |
| Declination | +10° 11′ 23.30″[1] |
| Apparent magnitude (V) | 6.04[2] |
| Characteristics | |
| Spectral type | F5 V Sr[3] |
| B−V color index | 0.447 ± 0.005[4] |
| Astrometry | |
| Radial velocity (Rv) | −9.9±0.2[5] km/s |
| Proper motion (μ) | RA: +42.022 mas/yr[1] Dec.: −180.181 mas/yr[1] |
| Parallax (π) | 26.2526 ± 0.057 mas[1] |
| Distance | 124.2 ± 0.3 ly (38.09 ± 0.08 pc) |
| Absolute magnitude (MV) | 3.24±0.03[2] |
| Details | |
| Mass | 1.23[6] M☉ |
| Radius | 1.6±0.1[7] R☉ |
| Luminosity | 4.59[4] L☉ |
| Surface gravity (log g) | 0.14±4.22[6] cgs |
| Temperature | 6,508±221[6] K |
| Metallicity [Fe/H] | −0.32[2] dex |
| Rotation | 3 days[8] |
| Age | 1.865[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 2454 is a probable binary star system in the zodiac constellation of Pisces. With an apparent visual magnitude of 6.04,[2] it is near the lower limit of visibility to the naked eye under good seeing conditions. An annual parallax shift of 26.3 mas as measured from Earth's orbit provides a distance estimate of 124 light years. It has a relatively high proper motion, traversing the celestial sphere at a rate of 0.208 arcseconds per year,[11] and is moving closer to the Sun with a heliocentric radial velocity of −10 km/s.[5]
The visible component of this system is an F-type main-sequence star with a stellar classification of F5 V Sr,[3] showing an abnormally strong line of singly-ionized strontium (Sr II) at a wavelength of 4077 Å.[12] It has an estimated 1.23[6] times the mass of the Sun and 1.6[7] times the Sun's radius. The star is about 1.9[6] billion years old with a rotation period of around three days.[8] It is radiating 4.6[4] times the Sun's luminosity from its photosphere at an effective temperature of around 6,508 K.[6]
HD 2454 was the first star to be identified as a Barium dwarf, by Tomkin et al. (1989),[13] and is the brightest such object.[2] It displays a mild overabundance of the element barium, which is hypothesized to have been accreted when an unresolved white dwarf companion was passing through the asymptotic giant branch (RGB) stage.[13]
The visible component displays significant overabundances of three s-process peak elements that are generated during the RGB phase, as well as a mild overabundance of carbon.[14] In contrast, it shows severe depletion of lithium and beryllium, as well as a notable underabundance of boron. The surface abundances of these lighter elements may have been altered during the mass transfer process, having been previously consumed in the core region of the companion.[15]
References
[edit]- ^ a b c d Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ a b c d e Gray, R. O.; et al. (May 2011), "First Direct Evidence That Barium Dwarfs Have White Dwarf Companions", The Astronomical Journal, 141 (5): 8, Bibcode:2011AJ....141..160G, doi:10.1088/0004-6256/141/5/160, 160.
- ^ a b Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2006), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637, S2CID 119476992.
- ^ a b c 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 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.
- ^ a b c d e f g 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.
- ^ a b Allen, D. M.; Barbuy, B. (August 2006), "Analysis of 26 barium stars. I. Abundances", Astronomy and Astrophysics, 454 (3): 895−915, arXiv:astro-ph/0604036, Bibcode:2006A&A...454..895A, doi:10.1051/0004-6361:20064912, S2CID 6378168.
- ^ a b Baliunas, S.; et al. (1996), "Magnetic Field and Rotation in Lower Main-Sequence Stars: an Empirical Time-dependent Magnetic Bode's Relation?", Astrophysical Journal Letters, 457 (2): L99, Bibcode:1996ApJ...457L..99B, doi:10.1086/309891.
- ^ Gould, Benjamin Apthorp (1879), "Uranometria Argentina catalog of bright southern stars", Resultados del Observatorio Nacional Argentino, 1, Bibcode:1879RNAO....1.....G, retrieved 2018-02-26.
- ^ "HD 2454". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-02-22.
- ^ Lépine, Sébastien; Shara, Michael M. (March 2005), "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)", The Astronomical Journal, 129 (3): 1483–1522, arXiv:astro-ph/0412070, Bibcode:2005AJ....129.1483L, doi:10.1086/427854, S2CID 2603568.
- ^ Gray, C. Richard O.; Corbally, J. (2009), Stellar Spectral Classification, Princeton University Press, pp. 247–248, ISBN 978-0691125114.
- ^ a b Tomkin, J.; et al. (July 1989), "HR 107 - an F-type mild barium dwarf star", Astronomy and Astrophysics, 219: L15−L18, Bibcode:1989A&A...219L..15T.
- ^ Roederer, Ian U. (September 2012), "Germanium, Arsenic, and Selenium Abundances in Metal-poor Stars", The Astrophysical Journal, 756 (1): 11, arXiv:1207.0518, Bibcode:2012ApJ...756...36R, doi:10.1088/0004-637X/756/1/36, S2CID 118407008, 36.
- ^ Boesgaard, Ann Merchant; et al. (March 2005), "Boron Depletion in F and G Dwarf Stars and the Beryllium-Boron Correlation", The Astrophysical Journal, 621 (2): 991−998, arXiv:astro-ph/0411246, Bibcode:2005ApJ...621..991B, doi:10.1086/427687, S2CID 8994810.
