Star in the constellation Sagittarius
9 Sagittarii
Location of 9 Sagittarius (circled)
Observation dataEpoch J2000 Equinox J2000
Constellation
Sagittarius
Right ascension
18h 03m 52.44501s [ 1]
Declination
−24° 21′ 38.6323″[ 1]
Apparent magnitude (V)
5.97[ 2]
Characteristics
Spectral type
O4V((f))z[ 3] (O3.5V((f+)) + O5–5.5V((f))[ 4] )
U−B color index
−0.89[ 2]
B−V color index
0.00[ 2]
Astrometry Radial velocity (Rv )10.70[ 5] km/s Proper motion (μ) RA: +0.539[ 1] mas /yr Dec.: −2.019[ 1] mas /yr Parallax (π)0.8001 ± 0.0728 mas [ 1] Distance 4,100 ± 400 ly (1,200 ± 100 pc ) Absolute magnitude (MV )−6.20[ 4]
Orbit [ 6] Period (P) 3,261± 69 d Semi-major axis (a)4,100 R ☉ [ 7] Eccentricity (e) 0.648± 0.009Inclination (i) 86.5± 0.5 °Semi-amplitude (K1 ) (primary) 36+4 −1 km/sSemi-amplitude (K2 ) (secondary) 49± 3 km/s
Details[ 6] 9 Sgr A Mass 32.1± 16.0 M ☉ Radius 10.8± 1.0 R ☉ Luminosity 479,000 L ☉ Surface gravity (log g ) 3.87± 0.20 cgs Temperature 46,000± 1,000 K Rotational velocity (v sin i ) 102+8 −12 km/s9 Sgr B Mass 18.9± 10.1 M ☉ Radius 8.9± 1.2 R ☉ Luminosity 224,000 L ☉ Surface gravity (log g ) 3.87± 0.20 cgs Temperature 42,000± 1,000 K Rotational velocity (v sin i ) 67+6 −13 km/sAge ~1 Myr
Other designations 9 Sgr,
HR 6736,
HIP 88469,
HD 164794,
CD −24°13814,
2MASS J18035245-2421386,
WDS J18039-2422
Database references SIMBAD data
9 Sagittarii (9 Sgr ) is a massive binary star in the constellation Sagittarius . It has an apparent magnitude of 5.97. Both components are highly luminous O-type main-sequence stars .
^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties" . Astronomy and Astrophysics . 674 : A1. arXiv :2208.00211 . Bibcode :2023A&A...674A...1G . doi :10.1051/0004-6361/202243940 . S2CID 244398875 .
Gaia DR3 record for this source at VizieR .
^ a b c Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues . 2237 . Bibcode :2002yCat.2237....0D .
^ 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 (1): 10. arXiv :1312.6222 . Bibcode :2014ApJS..211...10S . doi :10.1088/0067-0049/211/1/10 . S2CID 118847528 .
^ a b Rauw, G.; Sana, H.; Spano, M.; Gosset, E.; Mahy, L.; De Becker, M.; Eenens, P. (2012). "9 Sagittarii: Uncovering an O-type spectroscopic binary with an 8.6 year period". Astronomy & Astrophysics . 542 : A95. arXiv :1205.3314 . Bibcode :2012A&A...542A..95R . doi :10.1051/0004-6361/201219254 . S2CID 19967446 .
^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters . 32 (11): 759–771. arXiv :1606.08053 . Bibcode :2006AstL...32..759G . doi :10.1134/S1063773706110065 . S2CID 119231169 .
^ a b Cite error: The named reference fabry2021
was invoked but never defined (see the help page ).
^ Krtička, J.; Kubát, J.; Krtičková, I. (2015). "X-ray irradiation of the winds in binaries with massive components". Astronomy & Astrophysics . 579 : A111. arXiv :1505.03411 . Bibcode :2015A&A...579A.111K . doi :10.1051/0004-6361/201525637 . S2CID 119120927 .