Astronomy:Pi Tauri
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Taurus |
| Right ascension | 04h 26m 36.37093s[1] |
| Declination | +14° 42′ 49.6126″[1] |
| Apparent magnitude (V) | +4.69[2] |
| Characteristics | |
| Spectral type | G7 IIIa Fe-1[3] |
| U−B color index | +0.72[2] |
| B−V color index | +0.98[2] |
| Astrometry | |
| Radial velocity (Rv) | +31.4±0.3[4] km/s |
| Proper motion (μ) | RA: −9.52[1] mas/yr Dec.: −31.44[1] mas/yr |
| Parallax (π) | 7.83 ± 0.22[1] mas |
| Distance | 420 ± 10 ly (128 ± 4 pc) |
| Absolute magnitude (MV) | −1.27[5] |
| Details | |
| Mass | 3.94[5] M☉ |
| Radius | 21[6] R☉ |
| Luminosity | 229[7] L☉ |
| Surface gravity (log g) | 2.54[5] cgs |
| Temperature | 5,086[7] K |
| Metallicity [Fe/H] | −0.08[5] dex |
| Age | 17[5] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Pi Tauri (π Tauri) is a solitary,[9] yellow-hued star in the zodiac constellation of Taurus. With an apparent visual magnitude of +4.69,[2] it is bright enough to be visible to the naked eye. Although it appears to lie among the stars of the Hyades cluster, it is not itself a member, being three times farther from Earth than the cluster. The distance to this star, as determined using an annual parallax shift of 7.83 mas as seen from the Earth,[1] is around 420 light years. At that range, the visual magnitude of the star is diminished by an extinction factor of 0.24 due to interstellar dust.[5]
This is an evolved G-type giant star with a stellar classification of G7 IIIa Fe-1,[3] where the suffix notation indicates an underabundance of iron in the spectrum. The measured angular diameter is 1.55±0.06 mas.[10] At the estimated distance of Pi Tauri, this yields a physical size of about 21 times the radius of the Sun.[6] It possesses nearly four[5] times the mass of the Sun and is radiating 229 times the Sun's luminosity at an effective temperature of 5,086 K.[7]
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 Argue, A. N. (1966), "UBV photometry of 550 F, G and K type stars", Monthly Notices of the Royal Astronomical Society 133 (4): 475–493, doi:10.1093/mnras/133.4.475, Bibcode: 1966MNRAS.133..475A.
- ↑ 3.0 3.1 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, Bibcode: 1989ApJS...71..245K.
- ↑ 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, doi:10.1051/0004-6361/201219219, A61, Bibcode: 2012A&A...546A..61D.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 Takeda, Yoichi et al. (August 2008), "Stellar Parameters and Elemental Abundances of Late-G Giants", Publications of the Astronomical Society of Japan 60 (4): 781–802, doi:10.1093/pasj/60.4.781, Bibcode: 2008PASJ...60..781T.
- ↑ 6.0 6.1 Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1, https://books.google.com/books?id=OvTjLcQ4MCQC&pg=PA41. The radius (R*) is given by:
- [math]\displaystyle{ \begin{align} 2\cdot R_* & = \frac{(127.7\cdot 1.55\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\ & \approx 42.6\cdot R_{\bigodot} \end{align} }[/math]
- ↑ 7.0 7.1 7.2 McDonald, I. et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society 427 (1): 343–57, doi:10.1111/j.1365-2966.2012.21873.x, Bibcode: 2012MNRAS.427..343M.
- ↑ "pi Tau". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=pi+Tau.
- ↑ 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Richichi, A. et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics 431 (2): 773–777, doi:10.1051/0004-6361:20042039, Bibcode: 2005A&A...431..773R.
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