{{Short description|Binary star in the constellation of Delphinus}} {{Starbox begin | name = β 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=β Delphini |x=411|y=375 }} |caption=Location of β Delphini (circled) }} {{Starbox observe | epoch = J2000 | equinox = J2000 | ra = {{RA|20|37|32.94130}}<ref name=aaa474_2_653/> | dec = {{DEC|+14|35|42.3195}}<ref name=aaa474_2_653/> | appmag_v = {{val|3.617|0.016}}<ref name=aj138_5_1354/> {{nowrap|(4.11 + 5.01)}}<ref name=aaa341_121/> | constell = Delphinus }} {{Starbox character | class = {{nowrap|F5 III + F5 IV}}<ref name=aj81_245/> | b-v = A: {{val|0.43|0.14}}<br />B: {{val|0.56|0.25}}<ref name=aaa474_2_653/> | u-b = | variable = }} {{Starbox astrometry | component1 = Beta Delphini A | radial_v = | prop_mo_ra = +118.09<ref name=aaa474_2_653/> | prop_mo_dec = -48.06<ref name=aaa474_2_653/> | parallax = 32.33 | p_error = 0.47 | parallax_footnote = <ref name=aaa474_2_653/> | absmag_v = {{val|1.58|0.12}}<ref name=aj138_5_1354/> | component2 = Beta Delphini B | absmag_v2 = {{val|2.79|0.14}}<ref name=aj138_5_1354/> }} {{Starbox orbit | reference = <ref name=aaa341_121/> | period = 26.660 | axis = 0.440 | eccentricity = 0.36 | inclination = 61 | node = 177 | periastron = {{val|1989.50|u=yr}} | periarg = 349 | k1 = 7.6<ref name=ncsbo/> }} {{Starbox detail | component1 = Beta Delphini A | mass = {{val|1.75|0.002}}<ref name=aj138_5_1354/> | radius = | gravity = 3.50<ref name=aaa409_251/> | luminosity = 24<ref name=aaa409_251/> | temperature = {{val|6587}}<ref name=aaa409_251/> | metal_fe = –0.05<ref name=aj138_5_1354/> | rotational_velocity = 49.8<ref name=aaa409_251/> | age_gyr = {{val|1.79|+0.17|-0.72}}<ref name=aj138_5_1354/> | component2 = Beta Delphini B | mass2 = {{val|1.47|0.04}}<ref name=aj138_5_1354/> | luminosity2 = 8<ref name=kaler/> }} {{Starbox catalog | names = Rotanev, Rotanen, Venator, β Del, Beta Delphini, Beta Del, 6 Delphini, 6 Del, BD+14 4369, HD 196524, HIP 101769, HR 7882, SAO 106316, WDS 20375+1436AB<ref name=sb0 /><ref name=wds /><ref name=bsc1 /> }} {{Starbox reference |Simbad=bet+Del }} {{Starbox end}} '''Beta Delphini''' ('''β Delphini''', abbreviated '''Beta Del''', '''β Del''') is a binary star in the constellation of Delphinus. It is the brightest star in Delphinus.
The two components of the system are designated Beta Delphini A (officially named '''Rotanev''' {{IPAc-en|'|r|ou|t|@|n|E|v}}, which is historically the name of the system)<ref name=Kunitzsch>{{cite book |last1=Kunitzsch |first1=Paul |last2=Smart |first2=Tim |date = 2006 |edition = 2nd rev. |title = A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations |publisher = Sky Pub |location = Cambridge, Massachusetts |isbn = 978-1-931559-44-7 }}</ref><ref name="IAU-LSN">{{cite web | url=https://www.iau.org/public/themes/naming_stars/ | title=Naming Stars | publisher=IAU.org | access-date=16 December 2017 | archive-date=10 March 2025 | archive-url=https://web.archive.org/web/20250310063743/https://www.iau.org/public/themes/naming_stars/ | url-status=dead }}</ref> and B.
==Nomenclature== ''β Delphini'' (Latinised to ''Beta Delphini'') is the binary's Bayer designation. The designations of the two components as ''Beta Delphini A'' and ''B'' derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).<ref name="planetnaming">{{cite arXiv |title=On the naming convention used for multiple star systems and extrasolar planets |date=2010 |eprint=1012.0707 |class=astro-ph.SR |last1= Hessman |first1=F. V. |last2= Dhillon |first2=V. S. |last3= Winget |first3=D. E. |last4= Schreiber |first4=M. R. |last5= Horne |first5=K. |last6= Marsh |first6=T. R. |last7= Guenther |first7=E. |last8= Schwope |first8=A. |last9= Heber |first9=U. }}</ref>
Beta Delphini bore a historical name, ''Rotanev'', which arose as follows: Niccolò Cacciatore was the assistant to Giuseppe Piazzi, and later his successor as Director of the Palermo Observatory. The name first appeared in Piazzi's Palermo Star Catalogue. When the Catalogue was published in 1814, the unfamiliar names ''Sualocin'' and ''Rotanev'' were attached to ''Alpha'' and ''Beta Delphini'', respectively. Eventually the Reverend Thomas Webb, a British astronomer, puzzled out the explanation.<ref name=r1>{{cite book|last1=Webb|first1=T.W.|title=Celestial Objects for Common Telescopes|date=1859|publisher=Longmans, Green and Co.|location=London|pages=193–194}}</ref> Cacciatore's name, ''Nicholas Hunter'' in English translation, would be Latinized to ''Nicolaus Venator''. Reversing the letters of this construction produces the two names. They have endured, the result of Cacciatore's little practical joke of naming the two after himself. How Webb arrived at this explanation 45 years after the publication of the catalogue is still a mystery.<ref>{{cite web|last1=Hurn |first1=Mark |title=Secrets of the 1814 Palermo Star Catalogue |url=http://www.star-names.freeserve.co.uk/SECRETS2.HTM |website=The Story of Star Names |publisher=Mark Hurn, Institute of Astronomy Library, Univ. of Cambridge |access-date=11 May 2015 |archive-url=https://web.archive.org/web/20160304023454/http://www.star-names.freeserve.co.uk/SECRETS2.HTM |archive-date=4 March 2016 }}</ref>
In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)<ref name="WGSN">{{citation | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN) | publisher=International Astronomical Union | access-date=22 May 2016 | postscript=. | archive-date=10 June 2016 | archive-url=https://web.archive.org/web/20160610172014/https://www.iau.org/science/scientific_bodies/working_groups/280/ | url-status=dead }}</ref> to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.<ref name="TriRpt18">{{cite web | url=https://www.iau.org/static/science/scientific_bodies/working_groups/280/wg-starnames-triennial-report-2015-2018.pdf | page=5 | title=WG Triennial Report (2015-2018) - Star Names | access-date=2018-07-14 | archive-date=2019-08-23 | archive-url=https://web.archive.org/web/20190823174756/https://www.iau.org/static/science/scientific_bodies/working_groups/280/wg-starnames-triennial-report-2015-2018.pdf | url-status=dead }}</ref> It approved the name ''Rotanev'' for the component Beta Delphini A on 12 September 2016 and it is now so included in the List of IAU-approved Star Names.<ref name="IAU-LSN"/>
In Chinese, {{lang|zh|瓠瓜}} ({{lang|zh-Latn|Hù Guā}}), meaning ''Good Gourd'', refers to an asterism consisting of Beta Delphini, Alpha Delphini, Gamma<sup>2</sup> Delphini, Delta Delphini, and Zeta Delphini.<ref>{{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}}.</ref>
==Properties== Beta Delphini was found to be a binary star system in 1873 by the American astronomer S. W. Burnham.<ref name=burnham1978/> The system consists of a pair of F-type stars that orbit each other with a period of 26.66 years and an eccentricity of 0.36. The plane of the orbit is inclined by an angle of 61° to the line of sight from the Earth. The two stars have an angular separation of about 0.44 arcseconds, making them a challenge to resolve with a telescope. The larger member of the pair is a giant star with 1.75 times the mass<ref name=aj138_5_1354/> and 24 times the luminosity of the Sun,<ref name=aaa409_251/> while the secondary component is a subgiant star that has 1.47 times the Sun's mass<ref name=aj138_5_1354/> and around 8 times the Sun's luminosity.<ref name=kaler/> The system is around 1.8 billion years old.<ref name=aj138_5_1354/>
==See also== * Sualocin and Rotanev
==References== {{reflist|30em|refs=
<ref name=aaa474_2_653>{{citation | first=F. | last=van Leeuwen |date=November 2007 | title=Validation of the new Hipparcos reduction | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 |arxiv = 0708.1752 | s2cid=18759600 }}</ref>
<ref name=aj138_5_1354>{{citation | display-authors=1 | last1=Davidson | first1=James W. Jr. | last2=Baptista | first2=Brian J. | last3=Horch | first3=Elliott P. | last4=Franz | first4=Otto | last5=van Altena | first5=William F. | title=A Photometric Analysis of Seventeen Binary Stars Using Speckle Imaging | journal=The Astronomical Journal | volume=138 | issue=5 | pages=1354–1364 |date=November 2009 | doi=10.1088/0004-6256/138/5/1354 | bibcode=2009AJ....138.1354D | doi-access=free }}</ref>
<ref name=burnham1978>{{citation | first1=Robert | last1=Burnham | title=Burnham's celestial handbook: an observer's guide to the universe beyond the Solar System | volume=2 | series=Dover Books on Astronomy | edition=2nd | publisher=Courier Dover Publications | year=1978 | isbn=0-486-23568-8 | page=820 | url=https://books.google.com/books?id=wB9uZ9lH5bgC&pg=PA820 }}</ref>
<ref name=ncsbo>{{citation | display-authors=1 | last1=Pourbaix | first1=D. | last2=Tokovinin | first2=A. A. | last3=Batten | first3=A. H. | last4=Fekel | first4=F. C. | last5=Hartkopf | first5=W. I. | last6=Levato | first6=H. | last7=Morrell | first7=N. I. | last8=Torres | first8=G. | last9=Udry | first9=S. | title=SB9: The ninth catalogue of spectroscopic binary orbits | journal=Astronomy and Astrophysics | volume=424 | pages=727–732 |date=September 2004 | doi=10.1051/0004-6361:20041213 | bibcode=2004A&A...424..727P |arxiv = astro-ph/0406573 | s2cid=119387088 }}</ref>
<ref name=aaa409_251>{{citation | last1=Mallik | first1=Sushma V. | last2=Parthasarathy | first2=M. | last3=Pati | first3=A. K. | title=Lithium and rotation in F and G dwarfs and subgiants | journal=Astronomy and Astrophysics | volume=409 | pages=251–261 |date=October 2003 | doi=10.1051/0004-6361:20031084 | bibcode=2003A&A...409..251M | doi-access=free }}</ref>
<ref name=aaa341_121>{{citation | last1=Söderhjelm | first1=Staffan | title=Visual binary orbits and masses post Hipparcos | journal=Astronomy and Astrophysics | volume=341 | pages=121–140 |date=January 1999 | bibcode=1999A&A...341..121S }}</ref>
<ref name=aj81_245>{{citation | last1=Edwards | first1=T. W. | title=MK classification for visual binary components | journal=Astronomical Journal | volume=81 | pages=245–249 |date=April 1976 | doi=10.1086/111879 | bibcode=1976AJ.....81..245E }}</ref>
<ref name=bsc1>[http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=V/50/catalog&recno=7882 HR 7882] {{Webarchive|url=https://web.archive.org/web/20220127164706/http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=V/50/catalog&recno=7882 |date=2022-01-27 }}, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID [http://vizier.u-strasbg.fr/viz-bin/Cat?V/50 V/50]. Accessed on line October 1, 2008.</ref>
<ref name=kaler>[http://www.astro.uiuc.edu/~kaler/sow/rotanev.html Rotanev] {{webarchive |url=https://web.archive.org/web/20081121124003/http://www.astro.uiuc.edu/~kaler/sow/rotanev.html |date=November 21, 2008 }}, ''Stars'', Jim Kaler. Accessed on line October 1, 2008.</ref>
<ref name=sb0>{{SIMBAD link|beta+del|HD 196524 -- Spectroscopic binary}}, database entry, SIMBAD. Accessed on line October 1, 2008.</ref>
<ref name=wds>Entry 20375+1436, [http://ad.usno.navy.mil/wds/wdsnewframe4.html The Washington Double Star Catalog] {{webarchive |url=https://web.archive.org/web/20080908010456/http://ad.usno.navy.mil/wds/wdsnewframe4.html |date=September 8, 2008 }}, United States Naval Observatory. Accessed on line October 1, 2008.</ref>
}}
==External links== * {{Cite web|title = Special Stars: Rotanev|url = http://jumk.de/astronomie/special-stars/rotanev.shtml|website = jumk.de|access-date = 2015-08-23|first = Juergen|last = Kummer}}
{{Stars of Delphinus}}
{{Authority control}}
{{DEFAULTSORT:Beta Delphini}} Category:Delphinus Category:F-type subgiants Category:F-type giants Category:Binary stars Delphini, Beta Delphini, 06 196524 101769 Rotanev BD+14 4369 7882 Category:Lucidae