Beta Comae Berenices

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Star
Beta Comae Bernices
Position of β Com in the constellation Haar der Berenice
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Berenike's hair
Right ascension 13 h 11 m 52.39 s
declination + 27 ° 52 ′ 41.5 ″
Apparent brightness 4.25 likes
Typing
B − V color index +0.58 
U − B color index +0.08 
Spectral class F9.5V
Astrometry
Radial velocity 5.46 km / s
parallax 109.54 ± 0.17  mas
distance 29.78 ± 0.05  Lj
9.13 ± 0.01  pc
Proper movement 
Rec. Share: −801.44  mas / a
Dec. portion: +882.04  mas / a
Physical Properties
Dimensions 1.15  M ☉
radius 1.106 ± 0.011  R ☉
Luminosity

1.357 ± 0.014  L ☉

Effective temperature 5,936 ± 33  K
Metallicity [Fe / H] +0.07
Rotation time 11-13 d
Age 1.5-2.5 billion  a
Other names
and catalog entries
Bayer name β Comae Berenices
Flamsteed name 43 Comae Berenices
Bonn survey BD +28 2193
Bright Star Catalog HR 4983 [1]
Henry Draper Catalog HD 114710 [2]
Gliese catalog FY 502 [3]
Hipparcos catalog HIP 64394 [4]
SAO catalog SAO 82706 [5]
Tycho catalog TYC 1996-2400-1 [6]Template: Infobox star / maintenance / specification of the TYC catalog
2MASS catalog 2MASS J13115238 + 2752411 [7]
Other names FK5 492, GCTP 3015.00, LFT 978, LHS 348, LTT 13815

Beta Comae Berenices ( β Comae Berenices , β Com ) is a main-sequence star in the constellation Coma Berenices , which is about 29.78 light years from the sun away. The Bayer designation "Beta" (β) suggests at first glance that it is the second brightest star in the constellation. In fact, however, its apparent magnitude is slightly higher than that of Alpha Comae Berenices . β Com can be observed with the naked eye, but it is hard to see in urban areas with high light pollution .

The star is similar to the Sun, but slightly larger and brighter in terms of its absolute brightness . Its spectral class is given with F9.5V, partly also with G0V. The effective temperature of its surface is 5,936 Kelvin . At around 3 billion years old, β Com is younger than the Sun.

Observations suggest a period of rotation of approximately 11 to 13 days. Its surface has an activity cycle of 16.6 years compared to the Sun's 11-year cycle . Possibly β Com also has a secondary activity cycle of 9.6 years. At times it was suspected that he had a spectroscopic companion . However, this was ruled out by more precise measurements of its radial velocity . There is also no evidence of an exoplanet or a debris disk around β Com.

The habitable zone of β Com, and thus the region where liquid water could exist on an Earth-like planet, extends between 0.981 and 1.042 AU from the star.

Individual evidence

  1. ↑ a b c d e f SIMBAD: Bet Com. Retrieved May 31, 2015 .
  2. ^ Johnson, HL et al .: UBVRIJKL photometry of the bright stars . bibcode : 1966CoLPL ... 4 ... 99J .
  3. ↑ a b Mallik, Sushma V .: Chromospheric activity in cool stars and the lithium abundance. Retrieved May 31, 2015 .
  4. ^ Takeda, G. et al .: Stellar parameters of nearby cool stars. II. Physical properties of ~ 1000 cool stars from the SPOCS catalog . bibcode : 2008yCat..21680297T .
  5. ↑ a b c d Boyajian, Tabetha S. et al .: Stellar Diameters and Temperatures I. Main Sequence A, F, & G Stars . arxiv : 1112.3316 .
  6. ↑ a b Donahue, Robert A .; Baliunas, Sallie L .: Evidence of differential surface rotation in the solar-type star HD 114710 . bibcode : 1992ApJ ... 393L..63D .
  7. ↑ a b Mamajek, Eric E .; Hillenbrand, Lynne A .: Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics . arxiv : 0807.1686 .
  8. ^ Gray, RO; Napier, MG; Winkler, LI: The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars . bibcode : 2001AJ .... 121.2148G .
  9. ^ Baliunas, SL et al .: Chromospheric variations in main-sequence stars . bibcode : 1995ApJ ... 438..269B .
  10. ^ Cantrell, Justin R. et al .: The Solar Neighborhood XXIX: The Habitable Real Estate of our Nearest Stellar Neighbors . arxiv : 1307.7038 .

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