Beta Comae Berenices

Beta Comae Berenices

Location of β Coma Bernices (upper left)
Observation data
Epoch J2000      Equinox J2000
Constellation Coma Berenices
Right ascension 13h 11m 52.39379s[1]
Declination +27° 52′ 41.4535″[1]
Apparent magnitude (V) 4.26[2]
Characteristics
Spectral type G0 V[3]
U−B color index +0.08[2]
B−V color index +0.58[4]
Astrometry
Radial velocity (Rv)+6.1[5] km/s
Proper motion (μ) RA: -803.372 ± 1.370[6] mas/yr
Dec.: +882.512 ± 0.526[6] mas/yr
Parallax (π)108.8951 ± 0.3487 mas[6]
Distance29.95 ± 0.10 ly
(9.18 ± 0.03 pc)
Absolute magnitude (MV)4.46[7]
Details
Mass1.15[8] M☉
Radius1.106 ± 0.011[9] R☉
Luminosity1.357 ± 0.014[9] L☉
Surface gravity (log g)4.38[4] cgs
Temperature5,936 ± 33[9] K
Metallicity [Fe/H]+0.07[4] dex
Rotation12.3 ± 1.1[10] days
Rotational velocity (v sin i)4.10 ± 0.06[11] km/s
Age1.5–2.5[12] Gyr
Other designations
43 Com, β Com, BD+28° 2193, FK5 492, Gl 502, HD 114710, HIP 64394, HR 4983, LHS 348, LTT 13815, SAO 82706.[13]
Database references
SIMBADdata
β Comae Berenices in optical light

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,[2] 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.

The star is similar to the Sun, being only slightly larger and brighter in absolute magnitude. It has a stellar classification of G0 V,[3] compared to G2 V for the Sun. The effective temperature of the outer envelope is 5,936 K,[9] giving it a yellow hue of a G-type star.[14] In terms of age it is younger than the Sun, being about 3 billion years old.[12]

Observations of short term variations in the chromatic activity suggest that the star undergoes differential rotation,[15] with a rotation period of about 11–13 days.[11] 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.[16] 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.[17]

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  2. ^ a b c Cite error: The named reference clpl4_99 was invoked but never defined (see the help page).
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  6. ^ a b c Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
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  11. ^ a b Cite error: The named reference apj475_303 was invoked but never defined (see the help page).
  12. ^ a b Cite error: The named reference apj687 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
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  16. ^ Cite error: The named reference apj438_1_269 was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference aaa555_A104 was invoked but never defined (see the help page).