Semi-amplitude (K2)
(secondary) 339.4 km/s | Luminosity 45,500 Lā | |
V3903 Sagittarii is an eclipsing binary star system in the constellation Sagittiarus.
Contents
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.
Variability
V3903 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.
Distance
The distance derived from the annual parallax measured by the Hipparcos satellite is around 459 parsecs (1,500 ly), but the distance calculated from the physical properties of the two stars is 1,500 pc.
Properties
The system consists of two hot main-sequence stars. The spectral types have historically been accepted as O7V and O9V, 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 27 Mā and 19 Mā.