S Antliae

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S Antliae
SAntLightCurve.png
The blue light curve of S Antliae, adapted from Hogg & Bowe (1950) [1]
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☉
Luminosity3.4±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.

Contents

Characteristics

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

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

  1. ↑ 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 .
  2. ↑ 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.
  3. 1 2 3 4 5 6 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.
  4. 1 2 Watson, Christopher (4 January 2010). "S Antliae". AAVSO Website. American Association of Variable Star Observers . Retrieved 22 May 2014.
  5. 1 2 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.
  6. 1 2 3 4 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.
  7. 1 2 3 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.
  8. ↑ Paul, H. M. (1891). "Observations of 3407 S Antliae". Astronomical Journal. 10 (234): 139–142. Bibcode:1891AJ.....10..139P. doi: 10.1086/101491 .
  9. ↑ 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.
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