V539 Arae
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ara |
| Right ascension | 17h 50m 28.393s |
| Declination | −53° 36′ 44.66″ |
| Apparent magnitude (V) | 5.62 |
| Characteristics | |
| Spectral type | B2 V + B3 V + A1 V |
| U−B color index | −0.64 |
| B−V color index | −0.099±0.017 |
| Variable type | Algol/SPB |
| Astrometry | |
| Radial velocity (Rv) | −4.3±2.9 km/s |
| Proper motion (μ) | RA: +2.517 mas/yr Dec.: −12.105 mas/yr |
| Parallax (π) | 2.5208±0.1096 mas |
| Distance | 1,290 ± 60 ly (400 ± 20 pc) |
| Absolute magnitude (MV) | −1.83/−1.11 |
| Orbit | |
| Period (P) | 3.1690854(12) d |
| Eccentricity (e) | 0.0548(15) |
| Inclination (i) | 85.2° |
| Argument of periastron (ω) (secondary) | 118.9(1.2)° |
| Details | |
| V539 Ara A | |
| Mass | 6.239±0.066 M☉ |
| Radius | 4.551±0.019 R☉ |
| Luminosity | 2,000+240 −210 L☉ |
| Surface gravity (log g) | 3.9170±0.0029 cgs |
| Temperature | 18,100±500 K |
| Rotational velocity (v sin i) | 100 km/s |
| Age | 23.2±2.9 Myr |
| V539 Ara B | |
| Mass | 5.313±0.060 M☉ |
| Radius | 3.575±0.035 R☉ |
| Luminosity | 980+130 −110 L☉ |
| Surface gravity (log g) | 4.0570±0.0084 cgs |
| Temperature | 17,100±500 K |
| Rotational velocity (v sin i) | 130 km/s |
| Other designations | |
| Boss 4496, ν1 Arae, V539 Ara, CD−53°7423, GC 24187, HD 161783, HIP 87314, HR 6622, SAO 245065, PPM 346351, WDS J17505-5337A | |
| Database references | |
| SIMBAD | AB |
| A | |
V539 Arae is a multiple star system in the southern constellation of Ara. It has the Bayer designation Nu1 Arae , which is Latinized from ν1 Arae and abbreviated Nu1 Ara or ν1 Ara. This is a variable star system, the brightness of which varies from magnitude 5.71 to 6.24, making it faintly visible to the naked eye under good observing conditions. Based upon an annual parallax shift of 2.52 mas, this system is at a distance of approximately 1,290 light-years (400 parsecs) from Earth. The system is drifting closer to the Sun with a radial velocity of −4 km/s.
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. 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. In 1996, the secondary component was found to be a slowly pulsating B-type star (SPB) with periods of periods of 1.36, 1.78 and possibly 1.08 days.
The core members of this system, ν1 Ara AB, consist of a pair of B-type main-sequence stars in a detached orbit with a period of 3.169 days and an eccentricity of 0.055. 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. The eclipse of the primary causes a decrease of 0.52 in magnitude, while the secondary eclipse decreases the magnitude by 0.43.
At an angular separation of 12.34 arcseconds, is a possible tertiary component of this system; a magnitude 9.40 A-type main-sequence star with a classification of A1 V. A 2005 study of the orbit of the main pair demonstrated an apsidal motion, suggesting the influence of a third body. The initial estimate found an orbital period of 42.3±0.8 years and a mass of 1.63 M☉. In 2022, a more refined study suggested the influence of two stellar objects with masses of 0.41 M☉ and 1.74 M☉.
The system is sometimes referred as Upsilon1 Arae (υ1 Arae), and more generally unlettered.