epsilon Delphini
{{Short description|Star in the constellation Delphinus}}
{{Starbox begin
| name = ε Delphini
}}
{{Starbox image
| image=
{{Location mark
|image=Delphinus constellation map.svg|alt=|float=center|width=240
|label=|position=right
|mark=Red circle.svg|mark_width=10|mark_link=ε Del
|x=460|y=534
}}
|caption=Location of ε Delphini (circled)
}}
{{Starbox observe
| epoch = J2000.0
| constell = Delphinus
| dec = {{DEC|+11|18|11.7412}}
| appmag_v = 4.03 {{nowrap|(3.95−4.05)}}
}}
{{Starbox character
| r-i =
}}
{{Starbox astrometry
| radial_v = {{Val|−19.4|0.7}}
| parallax = 9.87
| p_error = 0.21
}}
{{Starbox detail
| source =
| mass =
| temperature = {{Val|13614|15|fmt=commas}}
| metal_fe = {{Val|+0.08|0.10}}
| rotational_velocity = {{Val|52|4}}
}}
{{Starbox catalog
| names = Aldulfin, {{odlist | B=ε Del | F=2 Del | BD=+10° 4321 | FK5=768 | HD=195810 | HIP=101421 | HR=7852 | SAO=106230 }}
}}
{{Starbox reference
| Simbad = HR+7852
}}
{{Starbox end}}
Epsilon Delphini (ε Delphini, abbreviated Eps Del, ε Del), officially named Aldulfin {{IPAc-en|æ|l|'|d|V|l|f|ən}},{{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars |publisher=IAU.org |accessdate=16 December 2017}} is a solitary, blue-white hued star in the northern constellation of Delphinus. It is visible to the naked eye with an apparent visual magnitude of 4.03. Based upon an annual parallax shift of 9.87 mas as seen from the Earth, the system is located about 330 light-years from the Sun. At Epsilon Delphini's distance, the visual magnitude is diminished by an extinction factor of 0.11 due to interstellar dust. The star is moving closer to the Sun with a radial velocity of −19 km/s.
This is a B-type giant star with a stellar classification of B6 III. It has 4.6 times the Sun's radius and is radiating 676 times the solar luminosity from its photosphere at an effective temperature of 13,614 K. The star may be slightly variable, occasionally brightening to magnitude 3.95. It is spinning with a projected rotational velocity of 52 km/s.
Proper names
ε Delphini (Latinised to Epsilon Delphini) is the star's Bayer designation.
The star bore the traditional Arabic name ðanab ad-dulfīn or Dzaneb al Delphin, which appeared in the catalogue of stars in the Calendarium of Al Achsasi Al Mouakket and which was translated into Latin as Cauda Delphini, meaning 'the dolphin's tail'. In 2016, the IAU organized a Working Group on Star Names (WGSN){{cite web | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN)|accessdate=22 May 2016}} to catalog and standardize proper names for stars. The WGSN approved the name Aldulfin for this star on 5 September 2017 and it is now so included in the List of IAU-approved Star Names.
In Chinese, {{lang|zh|敗瓜}} ({{lang|zh-Latn|Bài Guā}}), meaning Rotten Gourd, refers to an asterism consisting of Epsilon Delphini, Eta Delphini, Theta Delphini, Iota Delphini and Kappa Delphini.{{in lang|zh}} 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, {{ISBN|978-986-7332-25-7}}. Consequently, the Chinese name for Epsilon Delphini itself is {{lang|zh|敗瓜一}} ({{lang|zh-Latn|Bài Guā yī}}, {{langx|en|the First Star of Rotten Gourd}}.).{{in lang|zh}} [http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_c_d.htm 香港太空館 - 研究資源 - 亮星中英對照表] {{webarchive |url=https://web.archive.org/web/20090929163750/http://www.lcsd.gov.hk/CE/Museum/Space/Research/StarName/c_research_chinengstars_c_d.htm |date=September 29, 2009 }}, Hong Kong Space Museum. Accessed on line November 23, 2010. From this Chinese name, the name Pae Chaou was formed.
References
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| title=eps Del -- Variable Star
| work=SIMBAD Astronomical Database
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| url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=eps+Del
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}}
{{Stars of Delphinus|state=collapsed}}
{{Authority control}}
{{DEFAULTSORT:Epsilon Delphini}}