HD 165189 and HD 165190
Star in the constellation Corona Australis
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HD 165189 and HD 165190 are components of a visual binary star[10] system located 143 light years away in the southern constellation of Corona Australis. It is visible to the naked eye with the primary having an apparent visual magnitude of 4.929±0.025. The system is a member of the Beta Pictoris Moving Group.[14]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Corona Australis |
| HD 165189 | |
| Right ascension | 18h 06m 49.89293s[1] |
| Declination | −43° 25′ 30.8009″[1] |
| Apparent magnitude (V) | 5.62±0.01[2] |
| HD 165190 | |
| Right ascension | 18h 06m 49.91494s[3] |
| Declination | −43° 25′ 29.0976″[3] |
| Apparent magnitude (V) | 5.68±0.01[2] |
| Characteristics | |
| HD 165189 | |
| Spectral type | A6 V[4] |
| B−V color index | +0.230[5] |
| HD 165190 | |
| Spectral type | A7 V[4] |
| B−V color index | +0.262[5] |
| Astrometry | |
| Radial velocity (Rv) | −7.8±0.4[6] km/s |
| Absolute magnitude (MV) | +1.81[7] |
| HD 165189 | |
| Proper motion (μ) | RA: +10.915 mas/yr[1] Dec.: −105.835 mas/yr[1] |
| Parallax (π) | 22.7417±0.1025 mas[1] |
| Distance | 143.4 ± 0.6 ly (44.0 ± 0.2 pc) |
| HD 165190 | |
| Proper motion (μ) | RA: −1.187 mas/yr[3] Dec.: −101.243 mas/yr[3] |
| Parallax (π) | 22.6753±0.071 mas[3] |
| Distance | 143.8 ± 0.5 ly (44.1 ± 0.1 pc) |
| Orbit[8][9] | |
| Period (P) | 607±245 yr |
| Semi-major axis (a) | 4.63±1.83″ |
| Eccentricity (e) | 0.896±0.068 |
| Inclination (i) | 104±6° |
| Longitude of the node (Ω) | 84.2±5.5° |
| Periastron epoch (T) | 1854.7 |
| Argument of periastron (ω) (secondary) | 282±9° |
| Details | |
| HD 165189 | |
| Mass | 1.59[10] M☉ |
| Radius | 1.7[1] R☉ |
| Luminosity | 8.6[1] L☉ |
| Surface gravity (log g) | 4.25[11] cgs |
| Temperature | 7,600[1] K |
| Metallicity [Fe/H] | −0.25[11] dex |
| Rotational velocity (v sin i) | 130±1[12] km/s |
| HD 165190 | |
| Mass | 1.58[10] M☉ |
| Radius | 1.7[3] R☉ |
| Luminosity | 8.2[3] L☉ |
| Surface gravity (log g) | 4.15[11] cgs |
| Temperature | 7,566[3] K |
| Metallicity [Fe/H] | −0.24[11] dex |
| Rotational velocity (v sin i) | 129±1[12] km/s |
| Age | 813[3] Myr |
| Other designations | |
| 1 G. Coroane Australis, CD−43°12272, GC 24649, HIP 88726, CCDM J18068-4325, WDS J18068-4325[13] | |
| HD 165189: HR 6749 | |
| HD 165190: HR 6750 | |
| Database references | |
| SIMBAD | data |
| HD 165189 | |
| HD 165190 | |
The pair orbit each other with a period of 450 years and a large eccentricity of 0.650.[9] They have a projected separation of 70.1 AU.[10] Both components are A-type main-sequence stars; the primary has a stellar classification of A6 V while the secondary is A7 V.[14] They have similar masses of 1.59 and 1.58 times the mass of the Sun, respectively.[10]