Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
---|---|
Constellation | Sagittarius |
Right ascension | 19h 15m 32.42658s [1] |
Declination | −25° 15′ 24.0569″ [1] |
Apparent magnitude (V) | +4.86 [2] |
Characteristics | |
Spectral type | K2 III + A9 III + A3 V [3] |
B−V color index | 0.569±0.006 [2] |
Astrometry | |
Radial velocity (Rv) | −11.43±1.47 [4] km/s |
Proper motion (μ) |
RA: +45.50
[1]
mas/
yr Dec.: −31.08 [1] mas/ yr |
Parallax (π) | 10.93 ± 0.31 mas [1] |
Distance | 298 ± 8
ly (91 ± 3 pc) |
Absolute magnitude (MV) | 0.06 [2] |
Orbit [5] | |
Period (P) | 7,319 d |
Eccentricity (e) | 0.51 |
Periastron epoch (T) | 2442418.795 JD |
Argument of periastron (ω) (secondary) | 2.6° |
Semi-amplitude (K1) (primary) | 10.0 km/s |
Semi-amplitude (K2) (secondary) | 13.8 km/s |
Details | |
A | |
Mass | 2.10 [6] M☉ |
Luminosity | 84 [2] L☉ |
Ba/Bb | |
Mass | 1.70/2.70 M☉ |
Other designations | |
Database references | |
SIMBAD | data |
Psi Sagittarii, which is Latinized from ψ Sagittarii, is a triple star [8] system in the zodiac constellation of Sagittarius. The star system is located at a distance of 298 light years from the Earth based on parallax, but is drifting closer with a heliocentric radial velocity of −12 km/s. [4] The system is faintly visible to the naked eye has a combined apparent visual magnitude of +4.86. [2]
The inner pair of this triple star system, components Ba and Bb, have an orbital period of 10.78 days and an eccentricity of 0.47. [8] The pair consist of an A-type giant and a less evolved A-type main-sequence star with stellar classifications of A9 III + A3 V, [3] respectively. These in turn share an orbit with the primary, component A, having a period of 20 years and an eccentricity of 0.51. [5] The last is an orange-hued K-type giant with a class of K2 III. [3]
According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, this star was titled as Al Kiladah. [9] This star, together with τ Sgr, ν Sgr, ω Sgr, 60 Sgr and ζ Sgr were Al Udḥiyy, the Ostrich's Nest. [10]