V3903 Sagittarii
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 15h 15m 11.35199s[1] |
| Declination | +04° 56′ 21.7099″[1] |
| Apparent magnitude (V) | 7.00 - 7.45[2] |
| Characteristics | |
| Spectral type | O7V(n)z + B0:V:[3] |
| U−B color index | −0.82[4] |
| B−V color index | +0.16[4] |
| Variable type | Algol[5] |
| Astrometry | |
| Proper motion (μ) | RA: +0.87 ± 0.67[1] mas/yr Dec.: −0.66 ± 0.42[1] mas/yr |
| Parallax (π) | 2.18 ± 0.67[1] mas |
| Distance | 1,497[5] pc |
| Absolute magnitude (MV) | −4.59 + −3.69[5] |
| Orbit[5] | |
| Period (P) | 1.744204 days |
| Eccentricity (e) | 0 |
| Inclination (i) | 65.20° |
| Semi-amplitude (K1) (primary) | 236.6 km/s |
| Semi-amplitude (K2) (secondary) | 339.4 km/s |
| Details[5] | |
| A | |
| Mass | 27.27 M☉ |
| Radius | 8.088 R☉ |
| Luminosity | 122,000 L☉ |
| Surface gravity (log g) | 4.058 cgs |
| Temperature | 38,000 K |
| Rotational velocity (v sin i) | 230 km/s |
| B | |
| Mass | 19.01 M☉ |
| Radius | 6.125 R☉ |
| Luminosity | 45,500 L☉ |
| Surface gravity (log g) | 4.143 cgs |
| Temperature | 34,100 K |
| Rotational velocity (v sin i) | 170 km/s |
| Age | 1.6 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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.[6]
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.[7][5]
Distance
The distance derived from the annual parallax measured by the Hipparcos satellite is around 459 parsecs (1,500 ly),[1] but the distance calculated from the physical properties of the two stars is 1,500 pc.[5]
Properties
The system consists of two hot main-sequence stars. The spectral types have historically been accepted as O7V and O9V,[7] but the more recent Galactic O-Star Spectroscopic Survey gives a spectral type of O7V(n)z + B0:V:.[3] 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 M☉ and 19 M☉.[5]
References
- 1 2 3 4 5 6 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. Bibcode:2007A&A...474..653V. arXiv:0708.1752
. doi:10.1051/0004-6361:20078357. - ↑ Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
- 1 2 Sota, A.; Maíz Apellániz, J.; Morrell, N. I.; Barbá, R. H.; Walborn, N. R.; Gamen, R. C.; Arias, J. I.; Alfaro, E. J. (2014). "The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars". The Astrophysical Journal Supplement. 211: 10. Bibcode:2014ApJS..211...10S. doi:10.1088/0067-0049/211/1/10.
- 1 2 Schild, R. E.; Garrison, R. F.; Hiltner, W. A. (1983). "UBV photometry for southern OB stars". Astrophysical Journal Supplement Series (ISSN 0067-0049). 51: 321. Bibcode:1983ApJS...51..321S. doi:10.1086/190852.
- 1 2 3 4 5 6 7 8 Vaz, L. P. R.; Cunha, N. C. S.; Vieira, E. F.; Myrrha, M. L. M. (1997). "V 3903 Sagittarii: A massive main-sequence (O7V+O9V) detached eclipsing binary". Astronomy and Astrophysics. 327: 1094. Bibcode:1997A&A...327.1094V.
- ↑ Wagman, M. (1987). "Flamsteed's Missing Stars". Journal for the History of Astronomy. 18 (3): 209. Bibcode:1987JHA....18..209W. doi:10.1177/002182868701800305.
- 1 2 Weidner, C. (2010). "The masses, and the mass discrepancy of O-type stars". Astronomy & Astrophysics. 524: A98. Bibcode:2010A&A...524A..98W. arXiv:1010.2204 . doi:10.1051/0004-6361/201014491.