Astronomy:Pi Draconis
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Draco |
| Right ascension | 19h 20m 40.09333s[1] |
| Declination | +65° 42′ 52.3095″[1] |
| Apparent magnitude (V) | 4.59[2] |
| Characteristics | |
| Spectral type | A2 IIIs[3][4] |
| U−B color index | +0.06[2] |
| B−V color index | +0.02[2] |
| Astrometry | |
| Radial velocity (Rv) | −28.1±1.1[5] km/s |
| Proper motion (μ) | RA: +15.09[1] mas/yr Dec.: +41.12[1] mas/yr |
| Parallax (π) | 14.25 ± 0.12[1] mas |
| Distance | 229 ± 2 ly (70.2 ± 0.6 pc) |
| Absolute magnitude (MV) | +0.37[6] |
| Details | |
| Mass | 2.70[7] M☉ |
| Radius | 3.2[8] R☉ |
| Luminosity | 60[9] L☉ |
| Surface gravity (log g) | 3.80[10] cgs |
| Temperature | 9,125[10] K |
| Metallicity [Fe/H] | 0.42[6] dex |
| Rotational velocity (v sin i) | 26±1[3] km/s |
| Age | 350[7] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Pi Draconis, Latinized from π Draconis, is a solitary[7][4] star in the northern circumpolar constellation of Draco. It is visible to the naked eye with an apparent visual magnitude of 4.59.[2] Based upon an annual parallax shift of 14.25 mas as measured from Earth,[1] it is located around 229 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.063±0.10 due to interstellar dust.[12]
With an age of 350 million years, this is an A-type star of stellar classification A2 IIIs,[3][4] where the luminosity class of III typically indicates an evolved giant star and the 's' means the spectrum displays sharp absorption lines. It is a candidate Am star,[10] meaning there are some chemical peculiarities. The measured angular size is 0.427±0.062 arc seconds.[12] At the estimated distance of Pi Draconis, this yields a physical size of about 3.2 times the radius of the Sun.[8] It has about 2.70[7] times the mass of the Sun and is radiating 60[9] times the solar luminosity from its photosphere at an effective temperature of 9,125 K.[10]
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 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J.
- ↑ 3.0 3.1 3.2 Royer, F. et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics 393: 897–911, doi:10.1051/0004-6361:20020943, Bibcode: 2002A&A...393..897R.
- ↑ 4.0 4.1 4.2 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.
- ↑ Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters 32 (11): 759–771, doi:10.1134/S1063773706110065, Bibcode: 2006AstL...32..759G.
- ↑ 6.0 6.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 7.0 7.1 7.2 7.3 De Rosa, R. J. et al. (January 2014), "The VAST Survey - III. The multiplicity of A-type stars within 75 pc", Monthly Notices of the Royal Astronomical Society 437 (2): 1216–1240, doi:10.1093/mnras/stt1932, Bibcode: 2014MNRAS.437.1216D.
- ↑ 8.0 8.1 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{(70.2\cdot 0.427\cdot 10^{-3})\ \text{AU}}{0.0046491\ \text{AU}/R_{\bigodot}} \\ & \approx 6.4\cdot R_{\bigodot} \end{align} }[/math]
- ↑ 9.0 9.1 McDonald, I. et al. (2012), "Fundamental parameters and infrared excesses of Hipparcos stars", Monthly Notices of the Royal Astronomical Society 427 (1): 343–357, doi:10.1111/j.1365-2966.2012.21873.x, Bibcode: 2012MNRAS.427..343M.
- ↑ 10.0 10.1 10.2 10.3 Yüce, Kutluay; Adelman, Saul J. (April 2014), "Elemental Abundance Analyses with DAO Spectrograms. XXXIV. A Three-Dimensional Graphical Examination of the Elemental Abundances of the Mercury-Manganese and Metallic-Line Stars", Publications of the Astronomical Society of the Pacific 126 (938): 345, doi:10.1086/676335, Bibcode: 2014PASP..126..345Y.
- ↑ "pi. Dra". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=pi.+Dra.
- ↑ 12.0 12.1 van Belle, Gerard T.; von Braun, Kaspar (2009), "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars", The Astrophysical Journal 694 (2): 1085–1098, doi:10.1088/0004-637X/694/2/1085, Bibcode: 2009ApJ...694.1085V.
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