Zeta Delphini
Zeta Delphini (ζ Delphini) is a star in the constellation of Delphinus. With an apparent magnitude of about 4.6,[2] it is faintly visible to the naked eye. Parallax measurements of the system made by the Hipparcos spacecraft put it at a distance of about 220 light-years, or 67 parsecs.[1]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Delphinus |
| Right ascension | 20h 35m 18.53563s[1] |
| Declination | +14° 40′ 27.1675″[1] |
| Apparent magnitude (V) | +4.647[2] |
| Characteristics | |
| Spectral type | A3Va / L5[3] |
| U−B color index | +0.14[4] |
| B−V color index | +0.105[4] |
| Astrometry | |
| Radial velocity (Rv) | −25 ± 2[5] km/s |
| Proper motion (μ) | RA: 45.52[1] mas/yr Dec.: 11.74[1] mas/yr |
| Parallax (π) | 14.82 ± 0.23 mas[1] |
| Distance | 220 ± 3 ly (67 ± 1 pc) |
| Absolute bolometric magnitude (Mbol) | 0.523 / 14.59[3] |
| Details[3] | |
| ζ Del A | |
| Mass | 2.5 ± 0.2 M☉ |
| Luminosity | 48.63 ± 1.66 L☉ |
| Surface gravity (log g) | 3.72 cgs |
| Temperature | 8336 K |
| Metallicity [Fe/H] | −0.05 dex |
| Age | 525 ± 125 Myr |
| ζ Del B | |
| Mass | 55 ± 10 MJup |
| Luminosity | 0.00012 ± 0.00001 L☉ |
| Surface gravity (log g) | 5.0+0.5 −1.0 cgs |
| Temperature | 1550+250 −100 K |
| Age | 525 ± 125 Myr |
| Other designations | |
| Database references | |
| SIMBAD | ζ Del |
| ζ Del B | |
Zeta Delphini has a spectral type of A3V, implying it is an A-type main-sequence star.[3] These types of stars are bluish-white colored, and have effective temperatures between 7100 and 11500 K:[7] Zeta Delphini has a temperature of 8336 K.[3] Its age is estimated to be around 500 million years, considerably younger than the Sun.[3]
In 2014, the discovery of a brown dwarf around Zeta Delphini was announced. Zeta Delphini B is a brown dwarf with a spectral type of L5 (but may be from L3 to L7), and has a mass of about 55 Jupiters. At over 13 arcseconds away, this brown dwarf is separated at least 910 AU from Zeta Delphini.[3]
References edit
- ^ a b c d e f van Leeuwen, F.; et al. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
- ^ a b Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
- ^ a b c d e f g De Rosa, R. J.; Patience, J.; Ward-Duong, K.; Vigan, A.; Marois, C.; Song, I.; MacIntosh, B.; Graham, J. R.; Doyon, R.; Bessell, M. S.; Lai, O.; McCarthy, D. W.; Kulesa, C. (2014). "The VAST Survey - IV. A wide brown dwarf companion to the A3V star ζ Delphini". Monthly Notices of the Royal Astronomical Society. 445 (4): 3694. arXiv:1410.0005. Bibcode:2014MNRAS.445.3694D. doi:10.1093/mnras/stu2018. S2CID 34066734.
- ^ a b Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
- ^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode:1953GCRV..C......0W.
- ^ "zet+Del". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 5 March 2017.
- ^ Adelman, Saul J. (2004). "The physical properties of normal A stars". Proceedings of the International Astronomical Union. 2004: 1–11. Bibcode:2004IAUS..224....1A. doi:10.1017/S1743921304004314.