Astronomy:V539 Arae

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Short description: Triple star system in the constellation Ara
V539 Arae
Diagram showing star positions and boundaries of the Ara constellation and its surroundings
Cercle rouge 100%.svg
The location of V539 Arae (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Ara
Right ascension  17h 50m 28.39341s[1]
Declination –53° 36′ 44.6701″[1]
Apparent magnitude (V) 5.62[2]
Spectral type B2 V + B3 V + A1 V[2]
U−B color index –0.64
B−V color index –0.08
Variable type Algol variable
Radial velocity (Rv)-8[3] km/s
Proper motion (μ) RA: +3.18[1] mas/yr
Dec.: –11.40[1] mas/yr
Parallax (π)3.30 ± 0.47[1] mas
Distanceapprox. 1,000 ly
(approx. 300 pc)
Absolute magnitude (MV)–1.83/–1.11[4]
ν1 Ara A
Mass6.240 ± 0.066[4] M
Radius4.516 ± 0.084[4] R
Luminosity1,963[4] L
Surface gravity (log g)3.924 ± 0.016[4] cgs
Temperature18100 ± 500[4] K
Rotational velocity (v sin i)100[3] km/s
Age23.2 ± 2.9[5] Myr
ν1 Ara B
Mass5.314 ± 0.060[4] M
Radius3.428 ± 0.083[4] R
Luminosity902[4] L
Surface gravity (log g)4.093 ± 0.021[4] cgs
Temperature17100 ± 500[4] K
Rotational velocity (v sin i)130[3] km/s
Other designations
V539 Ara, CD−53° 7423, HD 161783, HIP 87314, HR 6622, SAO 245065.[6]
Database references

V539 Arae (Bayer designation Nu1 Arae1 Arae / ν1 Ara)) is a triple star system in the southern constellation of Ara. Based upon an annual parallax shift of 3.30 ± 0.47,[1] this system is at a distance of roughly 1,000 light-years (310 parsecs) from Earth.

The core members of this system, ν1 Ara AB, consist of a pair of B-type main sequence stars in a close orbit with a period of 3.169 days and an eccentricity of 0.06. Their respective stellar classifications are B2 V and B3 V, and they have a combined visual magnitude of 5.65. Because the orbital plane lies close to the line of sight from the Earth, this pair form a detached eclipsing binary of the Algol type.[6] The eclipse of the primary causes a decrease of 0.52 in magnitude, while the secondary eclipse decreases the magnitude by 0.43.[7] At an angular separation of 12.34 arcseconds, is the tertiary component of this system; a magnitude 9.40 A-type main sequence star with a classification of A1 V.[2]

The system is sometimes referred as Upsilon1 Arae1 Arae), and more generally unlettered.[8]


  1. 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode2008MNRAS.389..869E. 
  3. 3.0 3.1 3.2 Wilson, Ralph Elmer (1953), "General catalogue of stellar radial velocities", Carnegie Institute Washington D.C. Publication (Carnegie Institution of Washington), Bibcode1953GCRV..C......0W. 
  4. 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 Torres, G.; Andersen, J.; Giménez, A. (February 2010), "Accurate masses and radii of normal stars: modern results and applications", The Astronomy and Astrophysics Review 18 (1–2): 67–126, doi:10.1007/s00159-009-0025-1, Bibcode2010A&ARv..18...67T. 
  5. Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode2011MNRAS.410..190T. 
  6. 6.0 6.1 "V* V539 Ara". SIMBAD. Centre de données astronomiques de Strasbourg. 
  7. Malkov, O. Yu.; Oblak, E.; Snegireva, E. A.; Torra, J. (February 2006), "A catalogue of eclipsing variables", Astronomy and Astrophysics 446 (2): 785–789, doi:10.1051/0004-6361:20053137, Bibcode2006A&A...446..785M. 
  8. Note for HR 6622: Hoffleit, D., Warren, Jr., W. H., (1991). The Bright Star Catalogue, (5th Revised Ed).

External links