Zeta Delphini

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ζ Delphini
Delphinus constellation map.svg
Red circle.svg
Location of ζ Delphini (circled)
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]
Spectral type A3Va / L5[3]
U−B color index +0.14[4]
B−V color index +0.105[4]
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[1] mas
Distance220 ± 3 ly
(67 ± 1 pc)
Absolute bolometric
0.523 / 14.59[3]
ζ Del A
Mass2.5 ± 0.2 M
Luminosity48.63 ± 1.66 L
Surface gravity (log g)3.72 cgs
Temperature8336 K
Metallicity [Fe/H]−0.05 dex
Age525 ± 125 Myr
ζ Del B
Mass55 ± 10 MJup
Luminosity0.00012 ± 0.00001 L
Surface gravity (log g)5.0+0.5
Age525 ± 125 Myr
Other designations
BD+14° 4353, HD 196180, HIP 101589, HR 7871, SAO 106274[6]
Database references
ζ Del B

Zeta Delphini (ζ Del) 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]

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 light 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]


  1. ^ 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.
  2. ^ 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.
  3. ^ 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.
  4. ^ 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.
  5. ^ Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Washington. Bibcode:1953GCRV..C......0W.
  6. ^ "zet+Del". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 5 March 2017.
  7. ^ Adelman, Saul J. (2004). "The physical properties of normal A stars". Proceedings of the International Astronomical Union. 2004: 1. Bibcode:2004IAUS..224....1A. doi:10.1017/S1743921304004314.

External links[edit]

Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy & Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691.