1 Boötis
Binary star in the constellation Boötes
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1 Boötis (1 Boo) is a binary star[2] system in the northern constellation of Boötes, located 318 light years away from the Sun. It is visible to the naked eye as a dim, white-hued star with a combined apparent visual magnitude of 5.71.[5] The pair had an angular separation of 4.660″ as of 2008. It is moving closer to the Earth with a heliocentric radial velocity of −26 km/s.[6]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Boötes |
| A | |
| Right ascension | 13h 40m 40.46926s[1] |
| Declination | +19° 57′ 20.5839″[1] |
| Apparent magnitude (V) | 5.78[2] |
| A | |
| Right ascension | 13h 40m 40.46926s[3] |
| Declination | +19° 57′ 20.5839″[3] |
| Apparent magnitude (V) | 9.60[2] |
| Characteristics | |
| Spectral type | A1 V[4] + Am[2] |
| U−B color index | +0.02[5] |
| B−V color index | +0.02[5] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | −26[6] km/s |
| Proper motion (μ) | RA: −46.723[1] mas/yr Dec.: +23.172[1] mas/yr |
| Parallax (π) | 10.3308±0.0533 mas[1] |
| Distance | 316 ± 2 ly (96.8 ± 0.5 pc) |
| Absolute magnitude (MV) | +0.79[7] |
| B | |
| Proper motion (μ) | RA: −44,301[3] mas/yr Dec.: +28.326[3] mas/yr |
| Parallax (π) | 10.4702±0.0232 mas[3] |
| Distance | 311.5 ± 0.7 ly (95.5 ± 0.2 pc) |
| Details | |
| 1 Boö A | |
| Mass | 2.54±0.09[7] M☉ |
| Radius | 2.5[1] R☉ |
| Luminosity | 56[7] L☉ |
| Surface gravity (log g) | 3.90[1] cgs |
| Temperature | 9,863[7] K |
| Rotational velocity (v sin i) | 60[4] km/s |
| Age | 323[7] Myr |
| 1 Boö B | |
| Mass | 1.02[7] M☉ |
| Radius | 1.1[3] R☉ |
| Luminosity | 0.76[7] L☉ |
| Surface gravity (log g) | 4.28[3] cgs |
| Temperature | 5,370[7] K |
| Other designations | |
| BD+20°2858, HD 119055, HIP 66727, HR 5144, SAO 82942, CCDM J13407+1958, WDS J13407+1957[8] | |
| Database references | |
| SIMBAD | data |
| B | |
The magnitude 5.78[2] primary component is an A-type main-sequence star with a stellar classification of A1 V.[4] This star has 2.5 times the mass of the Sun[7] and is radiating 56 times the Sun's luminosity[7] from its photosphere at an effective temperature of 9,863 K.[7] It is 323 million years old[7] and is spinning with a projected rotational velocity of 60 km/s.[4]
The system is a source for X-ray emission, which is most likely coming from the companion star. This magnitude 9.60[2] component is a possible pre-main sequence star with a mass similar to the Sun. It is radiating 76% of the Sun's luminosity at an effective temperature of 6,370 K.[7]