| b-v = +0.16[5]
| u-b = −0.82[5]
| variable=Algol[7]
}}{{Starbox astrometry
| radial_v =
| prop_mo_ra = +0.87 ± 0.67[1]
| prop_mo_dec = −0.66 ± 0.42[1]
| parallax = 2.18
| p_error = 0.67
| parallax_footnote = [1]
| dist_pc = 1,497[7]
| absmag_v = −4.59 + −3.69[7]
}}{{Starbox orbit
| reference = [7]
| period_unitless = 1.744204 days
| eccentricity = 0
| inclination = 65.20
| k1 = 236.6
| k2 = 339.4
}}{{Starbox detail
| source = [7]
| component1 = A
| mass = 27.27
| radius = 8.088
| luminosity = 122,000
| temperature = 38,000
| metal_fe =
| gravity = 4.058
| rotational_velocity = 230
| component2 = B
| mass2 = 19.01
| radius2 = 6.125
| luminosity2 = 45,500
| temperature2 = 34,100
| metal_fe2 =
| gravity2 = 4.143
| rotational_velocity2 = 170
| age_myr2 = 1.6
}}{{Starbox catalog
| names = V3903 Sgr, CD−24° 13962, HD 165921, HIP 88943, SAO 186366
}}{{Starbox reference
| Simbad = V3903+Sgr
}}{{Starbox end}}V3903 Sagittarii is an eclipsing binary star system in the constellation Sagittiarus.
Nomenclature
John Flamsteed gave this star the Flamsteed designation 11 Sagittarii, although for some reason this designation is now more often used to refer to the star he designated 1 Sagittarii.[15]Properties
The system consists of two hot main-sequence stars. The spectral types have historically been accepted as O7V and O9V,[16] but the more recent Galactic O-Star Spectroscopic Survey gives a spectral type of O7V(n)z + B0:V:.[ The system is one of the youngest known eclipsing binaries, and one of the few containing such massive stars that have not yet filled their roche lobes. Their likely age is around 1.6 million years, and they have current masses of {{solar mass|27}} and {{solar mass|19}}.[7]]
V3903 Sagittarii varies in brightness. The General Catalogue of Variable Stars lists it as a possible hot irregular Orion variable star, but it has been shown to be a detached eclipsing binary system. The two stars are detached, that is they do not fill their roche lobes, which makes it an Algol-type eclipsing variable. The period is one day, 18 hours, 52 minutes.[16][7]
The distance derived from the annual parallax measured by the Hipparcos satellite is around {{convert|459|pc|ly}},[1] but the distance calculated from the physical properties of the two stars is 1,500 pc.[7]
References
1. ^1 {{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|author1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}
2. ^1 2 3 4 5 6 {{cite journal | title=Validation of the new Hipparcos reduction | last1=van Leeuwen | first1=F. | journal=Astronomy and Astrophysics | volume=474 | issue=2 | pages=653–664 | year=2007 | arxiv=0708.1752 | bibcode=2007A&A...474..653V | doi=10.1051/0004-6361:20078357 }}
3. ^1 2 3 4 5 6 7 8 {{cite journal|bibcode=1997A&A...327.1094V|title=V 3903 Sagittarii: A massive main-sequence (O7V+O9V) detached eclipsing binary|journal=Astronomy and Astrophysics|volume=327|pages=1094|author1=Vaz|first1=L. P. R.|last2=Cunha|first2=N. C. S.|last3=Vieira|first3=E. F.|last4=Myrrha|first4=M. L. M.|year=1997}}
4. ^1 2 {{cite journal|bibcode=1983ApJS...51..321S|title=UBV photometry for southern OB stars|journal=Astrophysical Journal Supplement Series|volume=51|pages=321|author1=Schild|first1=R. E.|last2=Garrison|first2=R. F.|last3=Hiltner|first3=W. A.|year=1983|doi=10.1086/190852}}
5. ^1 2 {{cite journal | doi = 10.1051/0004-6361/201014491 | title=The masses, and the mass discrepancy of O-type stars | journal=Astronomy & Astrophysics | date=2010 | volume=524 | pages=A98 | first=C. | last=Weidner | bibcode=2010A&A...524A..98W|arxiv = 1010.2204 }}
6. ^1 {{cite journal|bibcode=1987JHA....18..209W|doi=10.1177/002182868701800305|title=Flamsteed's Missing Stars|journal=Journal for the History of Astronomy|volume=18|issue=3|pages=209|year=1987|last1=Wagman|first1=M.}}