Triple star system in the constellation Ara From Wikipedia, the free encyclopedia
V539 Arae (Bayer designation Nu1 Arae (ν1 Arae / ν1 Ara)) is a triple star system in the southern constellation of Ara. It is a variable star, the brightness of which varies from magnitude 5.71 to 6.24, making it faintly visible to the naked eye under good observing conditions.[7] 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.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ara |
| Right ascension | 17h 50m 28.39341s[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 mas[1] |
| Distance | approx. 1,000 ly (approx. 300 pc) |
| Absolute magnitude (MV) | –1.83/–1.11[4] |
| Details | |
| ν1 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 | 18,100 ± 500[4] K |
| Rotational velocity (v sin i) | 100[3] km/s |
| Age | 23.2 ± 2.9[5] Myr |
| ν1 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 | 17,100 ± 500[4] K |
| Rotational velocity (v sin i) | 130[3] km/s |
| Other designations | |
| Database references | |
| SIMBAD | AB |
| A | |
In 1930, Ferdinand Johannes Neubauer found that the star (usually called Boss 4496 at the time) is a spectroscopic binary. He did not detect any brightness variability.[9] Eclipses were first reported by E. Schoeffel and U. Kohler in 1965. The period they reported is 1/2 the currently accepted value, because they did not realize that the light curve has a deep secondary minimum.[10][11]
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.[12] 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.[13]
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