Psi1 Draconis

{{Short description|Star in the constellation Draco}} {{DISPLAYTITLE:Psi¹ Draconis}} {{for|other star systems with a similar [[Bayer designation]]|Psi Draconis}} {{Starbox begin |name=ψ¹ Draconis }} {{Starbox image | image = {{Location mark |image=Draco constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=Psi1 Draconis |x=380|y=535 }} | caption = Location of ψ¹ Draconis (circled in red) }} {{Starbox observe 2s |constell=[[Draco (constellation)|Draco]] |epoch=[[J2000]] |component1=ψ¹ Dra A |ra1={{RA|17|41|56.35536}}<ref name=HIP>{{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}}</ref> |dec1={{DEC|+72|08|55.8481}}<ref name=HIP/> |appmag_v1=4.58<ref name=UBV>{{cite journal|title=UBVRIJKL Photometry of the Bright Stars|author1=Johnson, H. L.|journal=Communications of the Lunar and Planetary Laboratory|volume=4|pages=99|date=1966|bibcode=1966CoLPL...4...99J}}</ref> |component2=ψ¹ Dra B |ra2={{RA|17|41|58.10460}}<ref name=HIP/> |dec2={{DEC|+72|09|24.8581}}<ref name=HIP/> |appmag_v2=5.82<ref>{{cite journal|author1=Mermilliod, J.-C.|title=Compilation of Eggen's UBV data, transformed to UBV (unpublished)|journal=Catalogue of Eggen's UBV Data|url=http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1|date=1986|bibcode=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}}</ref> }} {{Starbox character |component1=ψ¹ Dra A |class=F5IV-V<ref name=SimbadA/> |b-v=+0.43<ref name=UBV/> |u-b=+0.01<ref name=UBV/> |component2=ψ¹ Dra B |class2=F8V<ref name=SimbadB/> |b-v2=+0.525<ref name=UBV/> |u-b2=+0.04<ref name=UBV/> }} {{Starbox astrometry |component1=ψ¹ Dra A |radial_v={{val|-13.30|0.2}}<ref name=RV>{{cite journal|title=Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system|author=Gontcharov, G. A.|date=2006|journal=Astronomy Letters|volume=32|issue=11|pages=759–771|bibcode=2006AstL...32..759G|doi=10.1134/S1063773706110065|arxiv=1606.08053|s2cid=119231169}}</ref> |prop_mo_ra=+25.32<ref name=HIP/> |prop_mo_dec=−268.47<ref name=HIP/> |parallax=43.79 |p_error=0.45 |parallax_footnote=<ref name=HIP/> |component2=ψ¹ Dra B |radial_v2={{val|-11.20|0.3}}<ref name=RV/> |prop_mo_ra2=+34.89<ref name=HIP/> |prop_mo_dec2=−275.94<ref name=HIP/> |parallax2=43.36 |p_error2=0.51 |parallax_footnote2=<ref name=HIP/> }} {{Starbox orbit |reference=<ref name=Gullikson/> |primary=ψ¹ Dra Aa |name=ψ¹ Dra Ab |period_unitless={{val|6774|+271|-167}} d |axis_unitless={{val|9.1|+0.4|-0.3}} [[Astronomical unit|AU]] |inclination={{val|31|1}} |eccentricity={{val|0.679|+0.006|-0.004}} |periarg={{val|32.6|0.7}} |periastron={{val|2450388|+169|-273}} |k1={{val|5.18|+0.04|-0.03}} |k2={{val|11.1|0.2}} }} {{Starbox detail |component1=ψ¹ Dra A |mass={{val|1.38|+0.15|-0.08}} / {{val|0.70|0.07}}<ref name=Gullikson>{{cite journal|doi=10.1088/0004-637X/815/1/62|arxiv=1511.01903|title= Mining Planet Search Data for Binary Stars: The ψ¹ Draconis system |journal=The Astrophysical Journal|volume=815|pages=62|year=2015|last1=Gullikson|first1=Kevin|last2=Endl|first2=Michael|last3=Cochran|first3=William D.|last4=MacQueen|first4=Phillip J.|issue=1|bibcode=2015ApJ...815...62G|s2cid=59408173}}</ref> |radius=1.2–1.3<ref name=CADARS>{{cite journal|display-authors=1|author1=Pasinetti Fracassini, L. E.|author2=Pastori, L.|author3=Covino, S.|author4=Pozzi, A.|title=Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) – Third edition – Comments and statistics|journal=Astronomy & Astrophysics|volume=367|issue=2|pages=521–24|date=2001|bibcode=2001A&A...367..521P|doi=10.1051/0004-6361:20000451|arxiv=astro-ph/0012289|s2cid=425754}}</ref> |temperature={{val|fmt=commas|6544|42}} / {{val|fmt=commas|4400|300}}<ref name=Gullikson/> |gravity={{val|3.90|0.11}}<ref name=Endl/> |metal_fe={{val|−0.10|0.05}}<ref name=Endl/> |component2=ψ¹ Dra B |temperature2={{val|fmt=commas|6212|75}}<ref name=Endl>{{cite journal|doi=10.3847/0004-637X/818/1/34|arxiv=1512.02965|title=Two New Long-Period Giant Planets from the Mcdonald Observatory Planet Search and Two Stars with Long-Period Radial Velocity Signals Related to Stellar Activity Cycles|journal=The Astrophysical Journal|volume=818|pages=34|year=2016|last1=Endl|first1=Michael|last2=Brugamyer|first2=Erik J.|last3=Cochran|first3=William D.|last4=MacQueen|first4=Phillip J.|last5=Robertson|first5=Paul|last6=Meschiari|first6=Stefano|last7=Ramirez|first7=Ivan|last8=Shetrone|first8=Matthew|last9=Gullikson|first9=Kevin|last10=Johnson|first10=Marshall C.|last11=Wittenmyer|first11=Robert|last12=Horner|first12=Jonathan|last13=Ciardi|first13=David R.|last14=Horch|first14=Elliott|last15=Simon|first15=Attila E.|last16=Howell|first16=Steve B.|last17=Everett|first17=Mark|last18=Caldwell|first18=Caroline|last19=Castanheira|first19=Barbara G.|issue=1|bibcode = 2016ApJ...818...34E |s2cid=39476347 |doi-access=free }}</ref> |gravity2={{val|4.20|0.12}}<ref name=Endl/> |radius2=1.5<ref name=CADARS/> |metallicity2={{val|0.01|0.06}}<ref name=Endl/> |mass2={{val|1.19|0.07}}<ref name=Endl/> |age_gyr2={{val|3.3|1.0}}<ref name=Endl/> }} {{Starbox catalog |names=Dziban, [[Flamsteed designation|31]] Dra, [[Aitken Double Star Catalog|ADS]] 10759 AB, [[Gliese Catalogue of Nearby Stars|Gliese]] 694.1 |component1=ψ¹ Dra A |names1=[[Bonner Durchmusterung|BD]]+72°804, [[Henry Draper Catalogue|HD]] 162003, [[Hipparcos catalogue|HIP]] 86614, [[Bright Star Catalog|HR]] 6636, [[Smithsonian Astrophysical Observatory Star Catalog|SAO]] 8890<ref name=SimbadA>{{cite simbad|title=psi01 Dra A|access-date=17 March 2017}}</ref> |component2=ψ¹ Dra B |names2=[[Bonner Durchmusterung|BD]]+72°805, [[Henry Draper Catalogue|HD]] 162004, [[Hipparcos catalogue|HIP]] 86620, [[Bright Star Catalog|HR]] 6637, [[Smithsonian Astrophysical Observatory Star Catalog|SAO]] 8891<ref name=SimbadB>{{cite simbad|title=psi01 Dra B|access-date=17 March 2017}}</ref> }} {{Starbox reference |Simbad=*+psi01+Dra|sn=ψ¹ Dra AB |Simbad2=*+psi01+Dra+A|sn2=ψ¹ Dra A |Simbad3=*+psi01+Dra+B|sn3=ψ¹ Dra B |NSTED=HR_6636 }} {{Starbox end}} '''Psi¹ Draconis''' ('''ψ¹ Draconis''', abbreviated '''Psi¹ Dra''', '''ψ¹ Dra'''), also designated '''31 Draconis''', is a [[Star system|triple star system]] in the northern [[constellation]] of [[Draco (constellation)|Draco]]. The system is fairly close, and is located about 75 [[light-year]]s (23 [[parsec]]s) from the [[Sun]], based on its [[stellar parallax|parallax]].<ref name=HIP/>

Psi¹ Draconis was considered a [[binary star]] consisting of an [[F-type star|F-type]] [[subgiant]] and an [[F-type main-sequence star]], designated Psi¹ Draconis A (officially named '''Dziban''' {{IPAc-en|'|z|ai|b|ən}},<!--the expected Latinized pronunciation--> from the traditional name of the system)<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 Psi¹ Draconis B, respectively. In 2015, Psi¹ Draconis A was itself found to be a double-lined [[spectroscopic binary]], making the system a triple. The companion to Psi¹ Draconis A was designated Psi¹ Draconis C by its discoverers.<ref name=Gullikson/>

Also in 2015, Psi¹ Draconis B was discovered to be orbited by an [[exoplanet]], designated Psi¹ Draconis Bb.<ref name=Endl/>

==Nomenclature== [[File:Psi1 Draconis.jpg|thumb|left|300px|ψ¹ Draconis in optical light]] ''ψ¹ Draconis'' ([[Latinisation of names|Latinised]] to ''Psi¹ Draconis'') is the system's [[Bayer designation]] and ''31 Draconis'' its [[Flamsteed designation]]. The designation of the components – ''ψ¹ Draconis A'' and ''B'' – derives from the convention used by the Washington Multiplicity Catalog (WMC) for [[multiple star system]]s, and adopted by the [[International Astronomical Union]] (IAU).<ref>{{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>

''Psi¹ Draconis'' bore the traditional name of ''Dziban'' or ''Dsiban,'' derived from the [[Arabic]] Adh-Dhi'ban, meaning "The two wolves" or "The two jackals".<ref name="allen">[https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Draco*.html Star Name – R.H. Allen p.212]</ref> In 2016, the IAU organized a [[IAU Working Group on Star Names|Working Group on Star Names]] (WGSN)<ref name="WGSN">{{cite web | url=https://www.iau.org/science/scientific_bodies/working_groups/280/ | title=IAU Working Group on Star Names (WGSN) | access-date=22 May 2016 | 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 catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire [[multiple star|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=2022-10-09 | archive-url=https://ghostarchive.org/archive/20221009/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 ''Dziban'' for the component Psi¹ Draconis A on 5 September 2017 and it is now so included in the List of IAU-approved Star Names.<ref name="IAU-LSN"/>

In [[Chinese astronomy]], Psi¹ Draconis is called 女史, [[Pinyin]]: Nǚshǐ, meaning ''Female Protocol'', because this star is marking itself and stands alone in the [[Asterism (astronomy)|asterism]] ''Female Protocol'' in the [[Purple Forbidden enclosure]] (see [[Chinese constellation]]).<ref>{{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0606/ap060610.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 10 日] {{Webarchive|url=https://web.archive.org/web/20110521234349/http://aeea.nmns.edu.tw/2006/0606/ap060610.html |date=2011-05-21 }}</ref> 女史 (Nǚshǐ) has been Latinised into ''Niu She'' by R.H. Allen, meaning "the Palace Governess", or "a Literary Woman".<ref name="allen"/>

==Properties== ψ¹ Draconis AC and ψ¹ Draconis B are separated by about 31 arcseconds. Only a very small fraction of the orbit has been observed: an [[orbital period]] of 10,000 years has been calculated,<ref name=ORB6>{{cite web|url=http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6|title=Sixth Catalog of Orbits of Visual Binary Stars|work=United States Naval Observatory|access-date=2017-03-24|archive-date=2017-04-30|archive-url=https://web.archive.org/web/20170430161106/http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6|url-status=dead}}</ref> but it is extremely preliminary and likely to be in high error.

ψ¹ Draconis A and C have varying [[radial velocity|radial velocities]] in respect to Earth, indicating that there must be orbital motion. The orbital period is estimated to be around 20 years, and the [[orbital eccentricity|eccentricity]] must be fairly high, around 0.679.<ref name=Gullikson/>

==Planetary system== Psi¹ Draconis Bb is a [[Jupiter]]-like [[exoplanet]] orbiting Psi¹ Draconis B, the secondary star. The planet was discovered when periodic [[Doppler shift]]s in the star's [[stellar spectrum|spectrum]] revealed the presence of a planet, similar to the spectroscopic binary nature of Psi¹ Draconis AC. Its [[minimum mass]] is {{jupiter mass|1.53|link=yes}}, and it orbits its host star every 8.5 years taking a relatively eccentric orbit.<ref name=Endl/>

{{OrbitboxPlanet begin | name = ψ¹ Draconis B | table_ref = <ref name=Endl/> }} {{OrbitboxPlanet | exoplanet = b | mass = ≥1.53 ± 0.10 | semimajor = 4.43 ± 0.04 | period = 3117 ± 42s | eccentricity = 0.40 ± 0.05 }} {{Orbitbox end}}

==References== {{reflist}}

{{Stars of Draco}}

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[[Category:Draco (constellation)]] [[Category:Bayer objects|Draconis, Psi1]] [[Category:Flamsteed objects|Draconis, 31]] [[Category:Planetary systems with one confirmed planet]] [[Category:F-type main-sequence stars]] [[Category:F-type subgiants]] [[Category:Hipparcos objects|086620]] [[Category:Bright Star Catalogue objects|6637]] [[Category:Henry Draper Catalogue objects|162003]] [[Category:Durchmusterung objects|BD+72 0804]] [[Category:Gliese and GJ objects|694.1]] [[Category:Spectroscopic binaries]] [[Category:Triple star systems]] [[Category:Stars with proper names|Dziban]]