Beta Comae Berenices
Beta Comae Berenices (β Comae Berenices, β Com) is a main sequence dwarf star in the northern constellation of Coma Berenices. It is located at a distance of about 29.95 light-years (9.18 parsecs) from Earth. The Greek letter beta (β) usually indicates that the star has the second highest visual magnitude in the constellation. However, with an apparent visual magnitude of 4.3, this star is actually slightly brighter than α Comae Berenices. It can be seen with the naked eye, but may be too dim to be viewed from a built-up urban area.
Location of β Coma Bernices (upper left) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Coma Berenices |
| Right ascension | 13h 11m 52.39379s |
| Declination | +27° 52′ 41.4535″ |
| Apparent magnitude (V) | 4.26 |
| Characteristics | |
| Spectral type | G0 V |
| U−B color index | +0.08 |
| B−V color index | +0.58 |
| Astrometry | |
| Radial velocity (Rv) | +6.1 km/s |
| Proper motion (μ) | RA: -803.372 ± 1.370 mas/yr Dec.: +882.512 ± 0.526 mas/yr |
| Parallax (π) | 108.8951 ± 0.3487 mas |
| Distance | 29.95 ± 0.10 ly (9.18 ± 0.03 pc) |
| Absolute magnitude (MV) | 4.46 |
| Details | |
| Mass | 1.15 M☉ |
| Radius | 1.106 ± 0.011 R☉ |
| Luminosity | 1.357 ± 0.014 L☉ |
| Surface gravity (log g) | 4.38 cgs |
| Temperature | 5,936 ± 33 K |
| Metallicity [Fe/H] | +0.07 dex |
| Rotation | 12.3 ± 1.1 days |
| Rotational velocity (v sin i) | 4.10 ± 0.06 km/s |
| Age | 1.5–2.5 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The star is similar to the Sun, being only slightly larger and brighter in absolute magnitude. It has a stellar classification of G0 V, compared to G2 V for the Sun. The effective temperature of the outer envelope is 5,936 K, giving it a yellow hue of a G-type star. In terms of age it is younger than the Sun, being about 3 billion years old.
Observations of short term variations in the chromatic activity suggest that the star undergoes differential rotation, with a rotation period of about 11–13 days. Its surface has a measured activity cycle of 16.6 years, compared to 11 years on the Sun. It may also have a secondary activity cycle of 9.6 years. At one time it was thought that this star might have a spectroscopic companion. However, this was ruled out by means of more accurate radial velocity measurements. No planets have yet been detected around it, and there is no evidence of a dusty disk.
The habitable zone for this star, defined as the locations where liquid water could be present on an Earth-like planet, is 0.918–1.96 AU, where 1 AU is the average distance from the Earth to the Sun.