Delta Sagittae
{{Short description|Binary star system in the constellation Sagitta}}
{{Starbox begin
| name = δ Sagittae
}}
{{Starbox image
| image=
{{Location mark
|image=Sagitta constellation map.svg|alt=|float=center|width=240
|label=|position=right
|mark=Red circle.svg|mark_width=10|mark_link=δ Sagittae
|x=390|y=257
}}
|caption=Location of δ Sagittae (circled)
}}
{{Starbox observe
| epoch=J2000
| constell=Sagitta
| appmag_v=+3.82{{nowrap|(3.91/ 6.64)}}
}}
{{Starbox character
| variable =LB?
}}
{{Starbox astrometry
| parallax = 5.9674
| p_error = 0.2597
}}
{{Starbox orbit
|axis=0.051
|periarg=257.7
|periastron=1979.93
|inclination=140.0
|node=170.2
}}
{{Starbox detail
|component1=δ Sge A
|temperature={{val|3660|170|fmt=commas}}
|component2=δ Sge B
}}
{{Starbox catalog
| names=δ Sagittae, 7 Sagittae, BD+18 4240, CCDM J19474+1832AB, FK5 743, GC 27391, HD 187076, HIP 97365, HR 7536, IDS 19429+1817 AB, PPM 136976, SAO 105259, WDS J19474+1832AB
}}
{{Starbox reference
|Simbad=del+Sge
}}
{{Starbox end}}
Delta Sagittae (Delta Sge, δ Sagittae, δ Sge) is a binary star in the constellation of Sagitta, with an apparent magnitude of +3.68. The primary component is a red M-type bright giant, and the secondary is a B-type main-sequence star. It is approximately 430 light years from Earth, based on its Gaia Data Release 2 parallax.
File:DeltaSgeLightCurve.png light curve for Delta Sagittae, plotted from data published by Tabur et al. (2009)]]
Delta Sagittae is a spectroscopic binary with a composite spectrum, meaning that light from both stars can be detected. It has an orbital period of about 10 years and an eccentricity of about 0.44. It is also a variable star, with its brightness changing between a maximum of magnitude 3.75 and a minimum of 3.83 in an unpredictable way.
Delta Sagittae is moving through the Galaxy at a speed of 9.8 km/s relative to the Sun. Its projected Galactic orbit carries it between 23,800 and 35,300 light years from the center of the Galaxy.{{Better source needed|reason=This source is inaccessible.|date=July 2017}}
{{clear left}}
Naming
In Chinese, {{lang|zh|左旗}} ({{lang|zh-Latn|Zuǒ Qí}}), meaning Left Flag, refers to an asterism consisting of δ Sagittae, α Sagittae, β Sagittae, ζ Sagittae, γ Sagittae, 13 Sagittae, 11 Sagittae, 14 Sagittae and ρ Aquilae. Consequently, the Chinese name for δ Sagittae itself is {{lang|zh|左旗三}} ({{lang|zh-Latn|Zuǒ Qí sān}}, {{langx|en|the Third Star of Left Flag}}.){{in lang|zh}} [http://aeea.nmns.edu.tw/2006/0607/ap060703.html AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 3 日] {{Webarchive|url=https://web.archive.org/web/20110521232833/http://aeea.nmns.edu.tw/2006/0607/ap060703.html |date=2011-05-21 }}
References
{{reflist|refs=
{{cite DR2|1824534959598087168}}
Calculated from subtracting magnitudes.
{{cite simbad|title=* del Sge|access-date=23 February 2017}}
{{cite Gaia EDR3|1824534959611831680}}
| title=A critical test of empirical mass loss formulas applied to individual giants and supergiants
| author1=Schröder, K.-P.|author2=Cuntz, M.
| journal=Astronomy and Astrophysics|volume=465|issue=2|pages=593–601
| date=2007|bibcode=2007A&A...465..593S|doi=10.1051/0004-6361:20066633
| arxiv=astro-ph/0702172|s2cid=55901104}}
| url=http://www.astrostudio.org/xhip.php?hip=97365
| title=Delta Sagittae (HIP 97365) |access-date=2012-09-17
| archive-url=https://web.archive.org/web/20130102054310/http://www.astrostudio.org/xhip.php?hip=97365
| archive-date=2013-01-02 |url-status=dead }}
| arxiv=1905.03744 |bibcode=2019AJ....158...20M |doi=10.3847/1538-3881/ab1cbd
| title=A Catalog of Known Galactic K-M Stars of Class I Candidate Red Supergiants in Gaia DR2
| year=2019 |last1=Messineo |first1=M. |last2=Brown |first2=A. G. A.
| journal=The Astronomical Journal |volume=158 |issue=1 |page=20 |s2cid=148571616 |doi-access=free }}
| title=Winds and accretion in delta Sagittae|author=Eaton, Joel A.
| author2=Hartkopf, William I.|author3=McAlister, Harold A.|author4=Mason, Brian D.
| journal=Astronomical Journal|volume=109|number=4|pages=1856–1866|date=1995
| bibcode=1995AJ....109.1856E|doi=10.1086/117412}}
| title=XHIP: An extended hipparcos compilation | last1=Anderson | first1=E.
| last2=Francis | first2=Ch. | journal=Astronomy Letters | volume=38
| issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A
| doi=10.1134/S1063773712050015 | arxiv=1108.4971 | s2cid=119257644
| postscript=. }}
| title=General catalogue of stellar radial velocities|author=Wilson, Ralph Elmer
| journal=Carnegie Institute Washington D.C. Publication|date=1953
| bibcode=1953GCRV..C......0W}}
| 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 }}
| bibcode=2009yCat....102025S
| title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)
| journal=VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S
| volume=1|pages=B/gcvs|display-authors=etal|last1=Samus|first1=N. N.
| last2=Durlevich|first2=O. V.|year=2009}}
| last1=Tabur |first1=V. |last2=Bedding |first2=T. R.
| last3=Kiss |first3=L. L. |last4=Moon |first4=T. T.
| last5=Szeidl |first5=B. |last6=Kjeldsen |first6=H.
| title=Long-term photometry and periods for 261 nearby pulsating M giants
| journal=Monthly Notices of the Royal Astronomical Society
| date=December 2009 |volume=400 |issue=4 |pages=1945–1961
| doi=10.1111/j.1365-2966.2009.15588.x |arxiv=0908.3228 |bibcode=2009MNRAS.400.1945T
|s2cid=15358380 |doi-access=free }}
}}
{{-}}
{{Stars of Sagitta}}
{{DEFAULTSORT:Delta Sagittae}}
Category:Durchmusterung objects