| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 02 16 30.58563 |
| Declination | −51° 30′ 43.7955″ |
| Apparent magnitude (V) | 3.55 |
| Characteristics | |
| Spectral type | B8IV-V |
| U−B color index | −0.38 |
| B−V color index | −0.12 |
| Astrometry | |
| Radial velocity (Rv) | 10.40 km/s |
| Proper motion (μ) | RA: +91.03 mas/yr Dec.: −22.23 mas/yr |
| Parallax (π) | 21.22 ± 0.12 mas |
| Distance | 153.7 ± 0.9 ly (47.1 ± 0.3 pc) |
| Absolute magnitude (MV) | 0.183±0.027 |
| Details | |
| Mass | 3.55 M☉ |
| Radius | 3.4 R☉ |
| Luminosity | 255 L☉ |
| Surface gravity (log g) | 4.21±0.14 cgs |
| Temperature | 13,716±466 K |
| Rotation | 0.343705 d |
| Rotational velocity (v sin i) | 250 km/s |
| Age | 44 Myr |
| Other designations | |
| φ Eri, CPD−52° 285, FK5 82, HD 14228, HIP 10602, HR 674, SAO 232696 | |
| Database references | |
| SIMBAD | data |
φ Eridani (Latinised as Phi Eridani) is a star in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude of 3.55. The distance to this star, as determined using the parallax method, is around 154 light-years.
This is a B-type star with a stellar classification of B8IV-V, suggesting it shows traits of a main-sequence star and a subgiant. It is spinning rapidly with a projected rotational velocity of 250 km/s. This rotation is giving the star an oblate shape with an equator that is 17% larger than the polar radius. The estimated angular size is 0.68 milliarcseconds. Since the distance is known, this yields a physical size of around 3.4 times the radius of the Sun. It has 3.55 times the mass of the Sun and radiates 255 times the solar luminosity from its outer atmosphere at an effective temperature of about 13,716 K.
Phi Eridani may form a wide binary star system with a 9th-magnitude star at lies an angular separation of 86″. This companion is a G-type main-sequence star with a stellar classification of G2V. It may also have a physical association with the naked-eye star Eta Horologii. It is a member of the Tucana-Horologium association, a 45(±4)-Myr-old group of stars that share a common motion through space.
References
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- ^ Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
- ^ Zuckerman, B.; Song, Inseok (2004), "Young Stars Near the Sun", Annual Review of Astronomy & Astrophysics, 42 (1): 685–721, Bibcode:2004ARA&A..42..685Z, doi:10.1146/annurev.astro.42.053102.134111.
- De Bruijne, J. H. J.; Eilers, A.-C. (2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: A61, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347.
- ^ Bell, Cameron P. M.; et al. (November 2015), "A self-consistent, absolute isochronal age scale for young moving groups in the solar neighbourhood", Monthly Notices of the Royal Astronomical Society, 454 (1): 593–614, arXiv:1508.05955, Bibcode:2015MNRAS.454..593B, doi:10.1093/mnras/stv1981.
- ^ 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.
- ^ Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
- McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
- Barraza, L. F.; Gomes, R. L.; Messias, Y. S.; Leão, I. C.; Almeida, L. A.; Janot-Pacheco, E.; Brito, A. C.; Brito, F. A. C.; Santana, J. V.; Gonçalves, N. S.; Das Chagas, M. L.; Teixeira, M. A.; De Medeiros, J. R.; Canto Martins, B. L. (2022). "Rotation Signature of TESS B-type Stars. A Comprehensive Analysis". The Astrophysical Journal. 924 (2): 117. arXiv:2202.01022. Bibcode:2022ApJ...924..117B. doi:10.3847/1538-4357/ac3335. S2CID 246030494.
- ^ van Belle, Gerard T. (March 2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20 (1): 51, arXiv:1204.2572, Bibcode:2012A&ARv..20...51V, doi:10.1007/s00159-012-0051-2, S2CID 119273474.
- "phi Eri". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-10-13.
{{cite web}}: CS1 maint: postscript (link) - 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.
- Shaya, Ed J.; Olling, Rob P. (January 2011), "Very Wide Binaries and Other Comoving Stellar Companions: A Bayesian Analysis of the Hipparcos Catalogue", The Astrophysical Journal Supplement, 192 (1): 2, arXiv:1007.0425, Bibcode:2011ApJS..192....2S, doi:10.1088/0067-0049/192/1/2, S2CID 119226823.
