S Antliae
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Antlia[2] |
| Right ascension | 09h 32m 18.38648s[3] |
| Declination | −28° 37′ 39.9685″[3] |
| Apparent magnitude (V) | 6.27 to 6.83[4] |
| Characteristics | |
| Spectral type | A9V |
| B−V color index | 0.33 |
| Variable type | Eclipsing binary W UMa type |
| Astrometry | |
| Proper motion (μ) | RA: −89.375 mas/yr[3] Dec.: +44.049 mas/yr[3] |
| Parallax (π) | 12.6116±0.0203 mas[3] |
| Distance | 258.6 ± 0.4 ly (79.3 ± 0.1 pc) |
| Absolute magnitude (MV) | 1.963[5] (2.25 + 3.42)[6] |
| Orbit[7] | |
| Period (P) | 0.59145447(30) days |
| Semi-major axis (a) | 3.82±0.02 R☉ |
| Inclination (i) | 74.02±0.14° |
| Semi-amplitude (K1) (primary) | 75±1 km/s |
| Semi-amplitude (K2) (secondary) | 234±1 km/s |
| Details[6] | |
| A | |
| Mass | 1.66±0.10 M☉ |
| Radius | 2.09±0.11 R☉ |
| Luminosity | 10.0±2.2 L☉ |
| Surface gravity (log g) | 4.02±0.03 cgs |
| Temperature | 7,100±200 K |
| B | |
| Mass | 0.55±0.05 M☉ |
| Radius | 1.31±0.06 R☉ |
| Luminosity | 3.4±0.7 L☉ |
| Temperature | 6,859±200 K |
| Age | 1.9[7] Gyr |
| Other designations | |
| CD-28°7373, HD 82610, SAO 177619, HIP 46810, HR 3798. | |
| Database references | |
| SIMBAD | data |
S Antliae is a W Ursae Majoris-type eclipsing binary star in Antlia.
Characteristics
[edit]S Antiliae is classed as an A-type W Ursae Majoris variable, since the primary is hotter than the secondary and the drop in magnitude is caused by the latter passing in front of the former. S Antiliae varies in apparent magnitude from 6.27 to 6.83 over a period of 15.6 hours.[4] The system shines with a combined spectrum of A9V.[citation needed]
The system's orbital period is about 0.591 days. The stars' centres are an average of 3.82 times the Sun's radius apart. The system will evolve into an Algol variable.[6]
Calculating the properties of the component stars indicates that the primary star has a mass 1.66 times and a diameter 2.09 times that of the Sun, and the secondary has a mass 0.55 times and a diameter 1.31 times that of the Sun. The primary has a surface temperature of 7,100 K, while the secondary is a little cooler at 6,859 K.[6] The two stars have similar luminosity and spectral type as they have a common envelope and share stellar material.[citation needed] The system is thought to be around two billion years old.[7]
Based upon an annual parallax shift of 12.6116 milliarc seconds as measured by the Gaia satellite,[3] this system is 259 light-years (79.3 parsecs) from Earth. Analysing and recalibrating yields a parallax of 13.30 and hence a distance of 250 light-years (76 parsecs).[5]
History
[edit]The star's variability was first recorded in 1888 by H.M. Paul,[8] when it had the shortest known period of any variable star. It was initially thought to be an Algol-type eclipsing binary, but this was discounted by E.C. Pickering on account of it lacking a shallow minimum in its maximum and the width of its minimum period. Alfred H. Joy noted the similarity of its light curve to W Ursae Majoris in 1926, concluding the system was indeed an eclipsing binary with two stars of spectral type A8.[9]
References
[edit]- ^ Hogg, A. R.; Bowe, P. W. A. (August 1950). "Photoelectric Observations of S Antliae". Monthly Notices of the Royal Astronomical Society. 110 (4): 373–380. doi:10.1093/mnras/110.4.373.
- ^ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
- ^ 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 Watson, Christopher (4 January 2010). "S Antliae". AAVSO Website. American Association of Variable Star Observers. Retrieved 22 May 2014.
- ^ a b Eker, Z.; Bilir, S.; Yaz, E.; Demircan, O.; Helvaci, M. (2009). "New absolute magnitude calibrations for W Ursa Majoris type binaries". Astronomische Nachrichten. 330 (1): 68–77. arXiv:0807.4989. Bibcode:2009AN....330...68E. doi:10.1002/asna.200811041. S2CID 15071352.
- ^ a b c d Bakis, Volkan; Budding, Edwin; Erdem, Ahmet; Love, Tom; Blackford, Mark G.; Zihao, Wu; Tang, Adam; Rhodes, Michael D.; Banks, Timothy S. (2024-09-25). "Comparative study of the W UMa type binaries S Ant and Epsilon CrA". Publications of the Astronomical Society of Australia. 41. arXiv:2409.17303. Bibcode:2024PASA...41...83B. doi:10.1017/pasa.2024.92.
- ^ a b c Latković, Olivera; Čeki, Atila; Lazarević, Sanja (2021). "Statistics of 700 Individually Studied W UMa Stars". The Astrophysical Journal Supplement Series. 254 (1): 10. arXiv:2103.06693. Bibcode:2021ApJS..254...10L. doi:10.3847/1538-4365/abeb23. S2CID 232185576.
- ^ Paul, H. M. (1891). "Observations of 3407 S Antliae". Astronomical Journal. 10 (234): 139–142. Bibcode:1891AJ.....10..139P. doi:10.1086/101491.
- ^ Joy, Alfred H. (1926). "Provisional elements and dimensions of S Antliae considered as an eclipsing binary". Astrophysical Journal. 64: 287–94. Bibcode:1926ApJ....64..287J. doi:10.1086/143015.
