zeta Delphini

{{short description|Star in the constellation Delphinus}}

{{Starbox begin|name=ζ Delphini}}

{{Starbox image

| image=

{{Location mark

|image=Delphinus constellation map.svg|alt=|float=center|width=260

|label=|position=right

|mark=Red circle.svg|mark_width=10|mark_link=ζ Del

|x=439|y=374

}}

|caption=Location of ζ Delphini (circled)

}}

{{Starbox observe

|epoch=J2000

|constell=Delphinus

|ra={{RA|20|35|18.53563}}{{cite journal|title=Validation of the new Hipparcos reduction|url=http://www.aanda.org/index.php?option=com_article&access=bibcode&Itemid=129&bibcode=2007A%2526A...474..653VFUL|author1=van Leeuwen, F.|display-authors=etal|journal=Astronomy and Astrophysics|volume=474|issue=2|pages=653–664|date=2007|arxiv=0708.1752|bibcode=2007A&A...474..653V|doi=10.1051/0004-6361:20078357|s2cid = 18759600}}

|dec={{DEC|+14|40|27.1675}}

|appmag_v=+4.647{{cite journal|title=The Tycho-2 catalogue of the 2.5 million brightest stars|author1=Høg, E.|display-authors=etal|date=2000|journal=Astronomy and Astrophysics|volume=355|pages=L27–L30|bibcode=2000A&A...355L..27H}}

}}

{{Starbox character

|class=A3Va / L5

|b-v=+0.105{{cite journal|author1=Mermilliod, J.-C.|title=Compilation of Eggen's UBV data, transformed to UBV (unpublished)|journal=Catalogue of Eggen's UBV Data|url=http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1|date=1986|bibcode= 1986EgUBV........0M }}

|u-b=+0.14

|variable=

}}

{{Starbox astrometry

|radial_v=−25 ± 2{{cite journal|title=General catalogue of stellar radial velocities|journal=Washington|author=Wilson, Ralph Elmer|date=1953|bibcode=1953GCRV..C......0W}}

|prop_mo_ra=45.52

|prop_mo_dec=11.74

|parallax=14.82

|p_error=0.23

|parallax_footnote=

|absmag_bol=0.523 / 14.59

}}

{{Starbox detail

|source={{cite journal|bibcode=2014MNRAS.445.3694D|arxiv=1410.0005|title=The VAST Survey - IV. A wide brown dwarf companion to the A3V star ζ Delphini|journal=Monthly Notices of the Royal Astronomical Society|volume=445|issue=4|pages=3694|last1=De Rosa|first1=R. J.|last2=Patience|first2=J.|last3=Ward-Duong|first3=K.|last4=Vigan|first4=A.|last5=Marois|first5=C.|last6=Song|first6=I.|last7=MacIntosh|first7=B.|last8=Graham|first8=J. R.|last9=Doyon|first9=R.|last10=Bessell|first10=M. S.|last11=Lai|first11=O.|last12=McCarthy|first12=D. W.|last13=Kulesa|first13=C.|year=2014|doi=10.1093/mnras/stu2018|doi-access=free |s2cid=34066734}}

|component1=ζ Del A

|mass=2.5 ± 0.2

|luminosity=48.63 ± 1.66

|temperature=8336

|gravity=3.72

|metal_fe=−0.05

|age_myr=525 ± 125

|component2=ζ Del B

|mass_mj2=55 ± 10

|luminosity2=0.00012 ± 0.00001

|temperature2={{val|1550|+250|-100}}

|gravity2={{val|5.0|+0.5|-1.0}}

|age_myr2=525 ± 125

}}

{{Starbox catalog

|names= 4 Delphini, BD+14°4353, HD 196180, HIP 101589, HR 7871, SAO 106274{{cite simbad|title=zet+Del|access-date=5 March 2017}}

}}

{{Starbox reference

|Simbad=zet+Del|sn=ζ Del

|Simbad2=zet+Del+B|sn2=ζ Del B

}}

{{Starbox end}}

Zeta Delphini (ζ Delphini) is a star in the constellation of Delphinus. With an apparent magnitude of about 4.6, 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.

Zeta Delphini has a spectral type of A3V, implying it is an A-type main-sequence star. These types of stars are bluish-white colored, and have effective temperatures between 7100 and 11500 K:{{cite journal|title=The physical properties of normal A stars|author=Adelman, Saul J.|journal=Proceedings of the International Astronomical Union|volume=2004|pages=1–11|date=2004|bibcode=2004IAUS..224....1A|doi=10.1017/S1743921304004314|doi-access=free}} Zeta Delphini has a temperature of 8336 K. Its age is estimated to be around 500 million years, considerably younger than the Sun.

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.