Rho Tucanae
Binary star system in the southern constellation Tucana
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Rho Tucanae (ρ Tuc, ρ Tucanae) is a binary star system in the southern constellation of Tucana. It is visible to the naked eye with a combined apparent visual magnitude of +5.38.[2] Based upon an annual parallax shift of 23.7 mas as seen from Earth, it is located 138 light years from the Sun.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Tucana |
| Right ascension | 00h 42m 28.37188s[1] |
| Declination | −65° 28′ 04.9066″[1] |
| Apparent magnitude (V) | +5.38[2] |
| Characteristics | |
| Evolutionary stage | main sequence[1] |
| Spectral type | F6 V[3] |
| U−B color index | +0.00[2] |
| B−V color index | +0.50[2] |
| Astrometry | |
| Radial velocity (Rv) | 33.962±0.796[4] km/s |
| Proper motion (μ) | RA: +53.444[1] mas/yr Dec.: +41.180[1] mas/yr |
| Parallax (π) | 23.6721±0.0631 mas[1] |
| Distance | 137.8 ± 0.4 ly (42.2 ± 0.1 pc) |
| Absolute magnitude (MV) | +2.75[5] |
| Orbit[6] | |
| Period (P) | 4.8202 d |
| Eccentricity (e) | 0.02 |
| Periastron epoch (T) | 2419299.11 JD |
| Semi-amplitude (K1) (primary) | 26.1 km/s |
| Details | |
| ρ Tuc A | |
| Mass | 1.66[7] M☉ |
| Luminosity | 9.7[8] L☉ |
| Surface gravity (log g) | 3.64±0.11[4] cgs |
| Temperature | 6,034±54[4] K |
| Metallicity [Fe/H] | −0.26[4] dex |
| Rotational velocity (v sin i) | 23.5±1.2[5] km/s |
| Age | 2.64[3] Gyr |
| ρ Tuc B | |
| Mass | 0.33[7] M☉ |
| Other designations | |
| ρ Tuc, CPD−66°47, FK5 2047, HD 4089, HIP 3330, HR 187, SAO 248237[9] | |
| Database references | |
| SIMBAD | data |
This is a single-lined spectroscopic binary with a close, nearly circular orbit having a period of 4.82 days and an eccentricity of 0.02.[6] The primary member, component A, is a yellow-white hued F-type main sequence star with a stellar classification of F6 V.[3] It is around 2.6 billion years old and a member of the thin disk population.[3] The primary has about 1.66 times the mass of the Sun while the secondary is just 0.33 times the Sun's mass.[7]