V539 Arae

V539 Arae (Bayer designation Nu¹ Arae (ν¹ 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.

"Nu1 Arae" redirects here. For other star systems with this Bayer designation, see Nu Arae.

V539 Arae

The location of V539 Arae (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Ara
Right ascension	17^h 50^m 28.39341^s[1]
Declination	–53° 36′ 44.6701″[1]
Apparent magnitude (V)	5.62[2]
Characteristics
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
Astrometry
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
Distance	approx. 1,000 ly (approx. 300 pc)
Absolute magnitude (MV)	–1.83/–1.11[4]
Details
ν^1 Ara A
Mass	6.240 ± 0.066[4] M☉
Radius	4.516 ± 0.084[4] R☉
Luminosity	1,963[4] L☉
Surface gravity (log g)	3.924 ± 0.016[4] cgs
Temperature	18100 ± 500[4] K
Rotational velocity (v sin i)	100[3] km/s
Age	23.2 ± 2.9[5] Myr
ν^1 Ara B
Mass	5.314 ± 0.060[4] M☉
Radius	3.428 ± 0.083[4] R☉
Luminosity	902[4] L☉
Surface gravity (log g)	4.093 ± 0.021[4] cgs
Temperature	17100 ± 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
SIMBAD	AB
	A

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 Arae (υ¹ Arae), and more generally unlettered.[8]

References

1. van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
3. Wilson, Ralph Elmer (1953), "General catalogue of stellar radial velocities", Carnegie Institute Washington D.C. Publication, Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
4. 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, arXiv:0908.2624, Bibcode:2010A&ARv..18...67T, doi:10.1007/s00159-009-0025-1.
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, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x.
6. "V* V539 Ara". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2010-07-31.
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, Bibcode:2006A&A...446..785M, doi:10.1051/0004-6361:20053137.
8. Note for HR 6622: Hoffleit, D., Warren, Jr., W. H., (1991). The Bright Star Catalogue, (5th Revised Ed).

External links

• VizieR Detailed Page: HR 6622
• AladinPreviewer: Image of Nu¹ Arae