ZZ Boötis
Eclipsing binary
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ZZ Boötis is a star system in the constellation Boötes. It varies from magnitude 6.79 to 7.44 over five days.[10] Based on its parallax, measured by the Gaia spacecraft, it is about 350 light-years (110 parsecs) away.[2]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Boötes |
| Right ascension | 13h 56m 09.5178s[2] |
| Declination | +25° 55′ 07.3547″[2] |
| Apparent magnitude (V) | 6.79–7.44[3] |
| Characteristics | |
| Spectral type | F2 IV-V + F2 IV-V[4] |
| B−V color index | +0.36[5] |
| Variable type | Algol[3] |
| Astrometry | |
| Radial velocity (Rv) | −29.50[6] km/s |
| Proper motion (μ) | RA: −97.004±0.057[2] mas/yr Dec.: −6.164±0.061[2] mas/yr |
| Parallax (π) | 9.3114±0.0381 mas[2] |
| Distance | 350 ± 1 ly (107.4 ± 0.4 pc) |
| Absolute bolometric magnitude (Mbol) | 2.507 / 2.382[7] |
| Orbit | |
| Period (P) | 4.99176522 ± 0.00000010 d[7] |
| Semi-major axis (a) | 18.024 ± 0.035 R☉[7] |
| Eccentricity (e) | 0.0[7] |
| Inclination (i) | 88.6361 ± 0.0044[7]° |
| Semi-amplitude (K1) (primary) | 93.7 ± 2.1[4] km/s |
| Semi-amplitude (K2) (secondary) | 94.0 ± 2.1[4] km/s |
| Details | |
| ZZ Boo A | |
| Mass | 1.5572 ± 0.0080[7] M☉ |
| Radius | 2.0626 ± 0.0057[7] R☉ |
| Luminosity | 10.7[4] L☉ |
| Surface gravity (log g) | 4.0016 ± 0.0019[7] cgs |
| Temperature | 6,720 ± 100[7] K |
| Metallicity [Fe/H] | −0.10 ± 0.08[8] dex |
| Rotational velocity (v sin i) | 20.905 ± 0.058[7] km/s |
| ZZ Boo B | |
| Mass | 1.599 ± 0.012[7] M☉ |
| Radius | 2.2050 ± 0.0062[7] R☉ |
| Luminosity | 9.95[4] L☉ |
| Surface gravity (log g) | 3.9550 ± 0.0023[7] cgs |
| Temperature | 6,690 ± 100[7] K |
| Metallicity [Fe/H] | −0.03 ± 0.10[8] dex |
| Rotational velocity (v sin i) | 22.348 ± 0.062[7] km/s |
| Other designations | |
| ZZ Boo, HD 121648, HIP 68064, SAO 83080, BD+26°2508[9] | |
| Database references | |
| SIMBAD | data |
Observational history
In 1950 Grigory Shajn determined that this star is a double-lined spectroscopic binary, with an approximate period of 4.96 days. Sergei Gaposchkin found from an examination of photographic plates, in 1951, that it was an Algol-type eclipsing binary system.[11] The primary and secondary eclipses are of equal depth, 0.65 magnitudes, meaning the brightness drops by nearly half.[3] The eclipses make up only 6% of the orbital period.[10]
ZZ Boötis is a binary star system, specifically an eclipsing binary.[10] The component stars appear to be of almost equal mass, differing by only 3%.[5]