Astronomy:Delta Pyxidis
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Pyxis |
| Right ascension | 08h 55m 31.56948s[1] |
| Declination | −27° 40′ 54.7315″[1] |
| Apparent magnitude (V) | +4.877[2] |
| Characteristics | |
| Spectral type | A3 IV[3] |
| U−B color index | +0.224[2] |
| B−V color index | +0.130[2] |
| Astrometry | |
| Radial velocity (Rv) | 5.4±0.8[4] km/s |
| Proper motion (μ) | RA: +81.90[1] mas/yr Dec.: −100.43[1] mas/yr |
| Parallax (π) | 13.19 ± 0.77[1] mas |
| Distance | 250 ± 10 ly (76 ± 4 pc) |
| Absolute magnitude (MV) | +0.67[5] |
| Details | |
| Mass | 1.84[6] M☉ |
| Radius | 1.6[7] R☉ |
| Luminosity | 59[3] L☉ |
| Surface gravity (log g) | 3.77±0.14[6] cgs |
| Temperature | 8,609±293[6] K |
| Rotational velocity (v sin i) | 68[6] km/s |
| Age | 296[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Delta Pyxidis (δ Pyxidis) is binary star[9] system in southern constellation of Pyxis. Having an apparent visual magnitude of +4.877,[2] it is bright enough to be visible to the naked eye. Based upon an annual parallax shift of 13.19 mas as seen from Earth,[1] it is located around 250 light years from the Sun.
In Chinese, 天狗 (Tiān Gǒu), meaning Celestial Dog, refers to an asterism consisting of δ Pyxidis, e Velorum, f Velorum, β Pyxidis, α Pyxidis and γ Pyxidis. Consequently, δ Pyxidis itself is known as 天狗七 (Tiān Gǒu qī, English: the Seventh Star of Celestial Dog.)[10]
This is an astrometric binary system, as determined by changes in the proper motion of the primary.[11] The visible component has a stellar classification of A3 IV,[3] indicating it has the spectrum of an A-type subgiant star that is consuming the last of the hydrogen at its core. At the age of around 296 million years,[6] it is 92.5%[3] of the way through its main sequence lifetime and is spinning with a projected rotational velocity of 68 km/s.[6] The star has an estimated 1.8[6] times the mass of the Sun and about 1.6[7] times the Sun's radius. It is radiating 59[3] times the Sun's luminosity from its photosphere at an effective temperature of roughly 8,609 K.[6]
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 Gutierrez-Moreno, Adelina et al. (1966), "A System of photometric standards", Publications of the Department of Astronomy University of Chile (Publicaciones Universidad de Chile, Department de Astronomy) 1: 1–17, Bibcode: 1966PDAUC...1....1G.
- ↑ 3.0 3.1 3.2 3.3 3.4 Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics 537: A120, doi:10.1051/0004-6361/201117691, Bibcode: 2012A&A...537A.120Z.
- ↑ 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.
- ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 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, doi:10.1088/0004-637X/804/2/146, Bibcode: 2015ApJ...804..146D.
- ↑ 7.0 7.1 Pasinetti Fracassini, L. E.; Pastori, L.; Covino, S.; Pozzi, A. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics 367: 521–524, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P.
- ↑ "del Pyx". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=del+Pyx.
- ↑ 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.
- ↑ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 17 日
- ↑ Frankowski, A. et al. (March 2007), "Proper-motion binaries in the Hipparcos catalogue. Comparison with radial velocity data", Astronomy and Astrophysics 464 (1): 377–392, doi:10.1051/0004-6361:20065526, Bibcode: 2007A&A...464..377F.
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