Α² Canum Venaticorum
 The location of α Canum Venaticorum (circled) |
|
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) |
|
|---|---|
| Constellation | Canes Venatici |
| α2 CVn | |
| Right ascension | 12h 56m 01.66622s |
| Declination | +38° 19′ 06.1541″ |
| Apparent magnitude (V) | 2.84 to 2.98 |
| α1 CVn | |
| Right ascension | 12h 56m 00.43258s |
| Declination | +38° 18′ 53.3768″ |
| Apparent magnitude (V) | 5.60 |
| Characteristics | |
| α2 CVn | |
| Spectral type | A0pSiEuHg |
| U−B color index | -0.32 |
| B−V color index | -0.12 |
| Variable type | α2 CVn |
| α1 CVn | |
| Spectral type | F2V |
| U−B color index | -0.03 |
| B−V color index | +0.34 |
| Astrometry | |
| α2 CVn | |
| Radial velocity (Rv) | -4.10 ± 0.2 km/s |
| Proper motion (μ) |
RA: −235.08 mas/yr Dec.: 53.54 mas/yr |
| Parallax (π) | 28.41 ± 0.90mas |
| Distance | 115 ± 4 ly (35 ± 1 pc) |
| Absolute magnitude (MV) | 0.16 ± 0.08 |
| α1 CVn | |
| Radial velocity (Rv) | -0.60 ± 0.9 km/s |
| Proper motion (μ) |
RA: −232.86 mas/yr Dec.: 55.69 mas/yr |
| Parallax (π) | 27.10 ± 9.54mas |
| Distance | approx. 120 ly (approx. 40 pc) |
| Details | |
| α2 CVn | |
| Mass | 2.97 ± 0.07 M☉ |
| Radius | 2.49 ± 0.26 R☉ |
| Luminosity | 101 ± 12 L☉ |
| Surface gravity (log g) | 3.9 ± 0.1 cgs |
| Temperature | 11600 ± 500 K |
| Rotation | 5.46939 d |
| Rotational velocity (v sin i) | 18.4 ± 0.5 km/s |
| Age |
165+60 −70 Myr |
| α1 CVn | |
| Mass | 1.47 ± 0.15 M☉ |
| Radius | 1.5 R☉ |
| Surface gravity (log g) | 4.25 ± 0.22 cgs |
| Temperature | 7080 K |
| Rotational velocity (v sin i) | 18 km/s |
| Other designations | |
| α2 CVn: α CVn A, 12 CVn A, FK5 485, GC 17557, HD 112413, HIP 63125, HR 4915, SAO 63257. | |
| α1 CVn: α CVn B, 12 CVn B, GC 17556, HD 112412, HIP 63121, HR 4914, SAO 63256. | |
| Database references | |
| SIMBAD | α2 CVn |
| α1 CVn | |
Cor Caroli is the traditional name for the binary star also designated Alpha Canum Venaticorum (α Canum Venaticorum, abbreviated Alpha CVn, α CVn), although the International Astronomical Union now regards the name as only applying to the brightest component. Alpha Canum Venaticorum is the brightest point of light in the northern constellation of Canes Venatici.
α Canum Venaticorum (Latinised to Alpha Canum Venaticorum) is the system's Bayer designation. The brighter of the two stars is designated α2 Canum Venaticorum, the fainter α1 Canum Venaticorum.
In the western world Alpha Canum Venaticorum had no name until the 17th century, when it was named Cor Caroli, which means "Charles's Heart". There has been some uncertainty whether it was named in honour of King Charles I of England, who was executed in 1649 during the English Civil War, or of his son, Charles II, who restored the English monarchy to the throne in 1660. The name was coined in 1660 by Sir Charles Scarborough, physician to Charles II, who claimed the star seemed to shine exceptionally brightly on the night of Charles II's return to England. In Star Names, R.H. Allen claimed that Scarborough suggested the name to Edmund Halley and intended it to refer to Charles II. However, Robert Burnham Jr. notes that "the attribution of the name to Halley appears in a report published by J. E. Bode at Berlin in 1801, but seems to have no other verification". In Star Tales, Ian Ridpath points out that the name's first appearance on a star map was in the 1673 chart of Francis Lamb, who labelled it Cor Caroli Regis Martyris ('the heart of Charles the martyred king'), clearly indicating that it was seen as referring to Charles I.
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