W Sagittarii

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

{{about|γ¹ Sagittarii|other stars with this Bayer designation|gamma Sagittarii{{!}}γ Sagittarii}}

{{Starbox begin

| name = W Sagittarii

}}

{{Starbox image

| image=

{{Location mark

|image=Sagittarius constellation map.svg|float=center

|alt=|label=|position=right|width=280

|mark=Red circle.svg|mark_width=10|mark_link=W Sagittarii

|x=668|y=524

}}

|caption=Location of W Sgr (circled)

}}

{{Starbox observe

| epoch = J2000

| ra = {{RA|18|05|01.22643}}

| dec = {{DEC|-29|34|48.3222}}

| appmag_v = {{nowrap|4.29 - 5.14}}

| constell = Sagittarius

}}

{{Starbox character

| component = Aa1

| class = F4 - G2Ib

| b-v = +0.78{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=CDS/ADC Collection of Electronic Catalogues|volume=2237|last1=Ducati|first1=J. R.|year=2002}}

| u-b = +0.52

| variable = δ Cep{{cite journal|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|display-authors=etal|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}

}}

{{Starbox character|no_heading=y

| component = Aa2

| class = A5V - F5V

| b-v =

| u-b =

| variable =

}}

{{Starbox character|no_heading=y

| component = Ab

| class = A0 V{{cite journal|bibcode=2013AJ....146...93E|arxiv=1307.7123|title=Binary Cepheids: Separations and Mass Ratios in 5 M ⊙ Binaries|journal=The Astronomical Journal|volume=146|issue=4|pages=93|last1=Evans|first1=Nancy Remage|last2=Bond|first2=Howard E.|last3=Schaefer|first3=Gail H.|last4=Mason|first4=Brian D.|last5=Karovska|first5=Margarita|last6=Tingle|first6=Evan|year=2013|doi=10.1088/0004-6256/146/4/93|s2cid=34133110}}

}}

{{Starbox astrometry

| radial_v = −28.04{{cite journal|bibcode=2004A&A...424..727P|title=SB9: The ninth catalogue of spectroscopic binary orbits|journal=Astronomy and Astrophysics|volume=424|issue=2|pages=727–732|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.|author-link7=Nidia Morrell|last8=Torres|first8=G.|last9=Udry|first9=S.|year=2004|doi=10.1051/0004-6361:20041213|arxiv = astro-ph/0406573 |s2cid=119387088}}

| prop_mo_ra = +4.372

| prop_mo_dec = −5.588

| parallax = 2.365

| p_error = 0.1765

| parallax_footnote = {{cite Gaia EDR3|4050309195613114624}}

| dist_pc =

| absmag_v = −3.76

}}

{{Starbox orbit

| reference = {{cite journal|bibcode=2007AJ....133.1810B|arxiv=astro-ph/0612465|title=Hubble Space Telescope Fine Guidance Sensor Parallaxes of Galactic Cepheid Variable Stars: Period-Luminosity Relations|journal=The Astronomical Journal|volume=133|issue=4|pages=1810|last1=Benedict|first1=G. Fritz|last2=McArthur|first2=Barbara E.|last3=Feast|first3=Michael W.|last4=Barnes|first4=Thomas G.|last5=Harrison|first5=Thomas E.|last6=Patterson|first6=Richard J.|last7=Menzies|first7=John W.|last8=Bean|first8=Jacob L.|last9=Freedman|first9=Wendy L.|year=2007|doi=10.1086/511980|s2cid=16384267 }}

| primary = Aa1

| name = Aa2

| period = {{val|4.33|0.01}}

| period_unitless =

| axis = 12.9 ± 0.3

| axis_unitless = 5.67 ± 0.13 AU

| eccentricity = 0.41 ± 0.02

| inclination = 7.0 ± 0.8

| node = 68.4 ± 4.0

| periastron = 2004.16 ± 0.01

| periarg = 328.0 ± 1.3

| k1 =

| k2 =

}}

{{Starbox orbit|no_heading=y

| reference =

| primary = Aa

| name = Ab

| period = 172.9

| period_unitless =

| axis =

| axis_unitless = 63 AU

| eccentricity =

| inclination =

| node =

| periastron =

| periarg =

| periarg_primary =

| k1 =

| k2 =

}}

{{Starbox detail

| component1 = Aa

| mass = 5.8

| radius = 61.0{{cite journal|bibcode=2007A&A...474..975G|title=The projection factor, period-radius relation, and surface-brightness colour relation in classical cepheids|journal=Astronomy and Astrophysics|volume=474|issue=3|pages=975–981|last1=Groenewegen|first1=M. A. T.|year=2007|doi=10.1051/0004-6361:20078225|doi-access=free}}

| luminosity = 2,690

| temperature = 5,380 - 6,474

| metal_fe = +0.02{{cite journal|bibcode= 2013AstL...39..851M|title= Properties of the population of classical Cepheids in the Galaxy|journal= Astronomy Letters|volume= 39|issue= 12|pages= 851|last1= Marsakov|first1= V. A.|last2= Koval'|first2= V. V.|last3= Kovtyukh|first3= V. V.|last4= Mishenina|first4= T. V.|year= 2013|doi= 10.1134/S1063773713120050|s2cid= 119788977}}

| gravity = 1.50 - 2.15{{cite journal|bibcode=2004AJ....128..343L|title=Phase-dependent Variation of the Fundamental Parameters of Cepheids. I. Periods from 6 to 10 Days|journal=The Astronomical Journal|volume=128|pages=343–356|last1=Luck|first1=R. E.|last2=Andrievsky|first2=S. M.|year=2004|issue=1|doi=10.1086/420991|doi-access=free}}

| rotational_velocity =

| component2 = Aa2

| mass2 = 1.4 - 2.0

| radius2 =

| luminosity2 =

| temperature2=

| metal_fe2 =

| gravity2 =

| rotational_velocity2 =

| age_myr2 =

}}

{{Starbox detail|no_heading=y

| component1 = Ab

| mass = 2.2

| radius =

| luminosity =

| temperature =

| metal_fe =

| gravity =

| rotational_velocity =

| age_myr =

}}

{{Starbox catalog

| names= γ¹ Sgr, W Sagittarii, HR 6742, HD 164975, SAO 186237, HIP 88567, ADS 11029, CCDM 18050-2935

}}

{{Starbox reference

| Simbad=W+Sgr

}}

{{Starbox end}}

W Sagittarii (W Sgr, Gamma¹ Sagittarii (γ¹ Sgr)) is a multiple star system star in the constellation Sagittarius, and a Cepheid variable star.

W Sagittarii is an optical line-of-sight companion nearly a degree from the much brighter γ² Sgr (Al Nasl) which marks the nozzle or spout of the teapot asterism.