Epsilon Boötis
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| Observation data Equinox J2000 |
|
|---|---|
| Constellation | Boötes |
| Right ascension | 14h 44m 59.2s |
| Declination | +27° 04′ 27.2″ |
| Apparent magnitude (V) | 2.39 (2.70/5.12) |
| Characteristics | |
| Spectral type | K0 II-III/A2 V |
| U-B color index | 0.73 |
| B-V color index | 0.97 |
| Variable type | ? |
| Astrometry | |
| Radial velocity (Rv) | −17 km/s |
| Proper motion (μ) | RA: −50.65 mas/yr Dec.: 20.00 mas/yr |
| Parallax (π) | 15.55 ± 0.78 mas |
| Distance | 210 ly (64.3 pc) |
| Absolute magnitude (MV) | −1.69/1.08 |
| Details | |
| Mass | 4/2 M☉ |
| Radius | 33/2 R☉ |
| Luminosity | 400/27 L☉ |
| Temperature | 4,800/8,700 K |
| Metallicity | 230% Sun |
| Rotation | |
| Age | 3 × 108 years |
| Other designations | |
| Database references | |
| SIMBAD | data |
Epsilon Boötis (ε Boo / ε Boötis) is a star in the constellation Boötes. It also has the traditional names Izar or Pulcherrima.
Izar is actually a binary star, consisting of a bright orange giant and a smaller main sequence star. The orange giant is a fairly late-stage star well into its stellar evolution, having already exhausted its supply of hydrogen fuel. By the time the smaller main sequence star reaches this point in its evolution, the primary star will have lost much of its mass in a planetary nebula and will have evolved into a white dwarf, and the pair will have essentially changed roles: the primary star becoming the dim dwarf, while the lesser A star will shine as a bright orange giant.
The name Izar is derived from the Arabic ازار izār "veil," and the name Pulcherrima is derived from the Latin for "loveliest."
[edit] In fiction
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