Wikipedia

Beta Comae Berenices

Beta Comae Berenices (afgekort as β Com) is ’n hoofreeksster in die noordelike sterrebeeld Berenike se Hare (Coma Berenices). Dit is sowat 29,95 ligjare van die Son af. Die Griekse letter beta (β) dui gewoonlik aan ’n ster is die tweede helderste in ’n spesifieke sterrebeeld, maar met ’n skynbare magnitude van 4,3[3] is dié ster die helderste. Dit kan op ’n donker nag met die blote oog gesien word.

Beta Comae Berenices
Die ligging van Beta Comae Berenices (in die rooi sirkel).
Die ligging van Beta Comae Berenices (in die rooi sirkel).
Sterrebeeld Berenike se Hare
Spektraaltipe G0 V[1]
Soort Hoofreeksster
Waarnemingsdata (Epog J2000)
Regte klimming 13h 11m 52.39379s[2]
Deklinasie +27° 52′ 41.4535″[2]
Skynmagnitude (m) 4,26[3]
Absolute magnitude (M) 4,46[4]
B-V-kleurindeks  +0,58[5]
U-B-kleurindeks  +0,08[3]
Besonderhede
Massa (M☉) 1,15[6]
Radius (R☉) 1,106 ± 0,011[7]
Ligsterkte (L☉) 1,357 ± 0,014[7]
Ouderdom (jaar) 1,5-2,5 miljard[8]
Temperatuur (K) 5 936 ± 33[7]
Rotasiespoed (km/s) 4,10 ± 0,06[9]
Metaalinhoud [Fe/H] +0,07[5]
Ander name
43 Com, β Com, BD+28° 2193, FK5 492, Gl 502, GJ 502, HD 114710, HIP 64394, HR 4983, LHS 348, LTT 13815, SAO 82706[10]
Portaal  Portaalicoon   Sterrekunde
β Comae Berenices in optiese lig.

β Com is baie soos die Son; dit is net effens groter en helderder in absolute magnitude. Dit het ’n sterreklassifikasie van G0 V,[1] in vergelyking met die Son se G2 V. Die oppervlaktemperatuur is 5 936 K,[7] en dus het dit die tipiese geel kleur van ’n G-tipe ster.[11] Op 3 miljard jaar is dit effens jonger as die Son.[8]

Volgens waarnemings ondergaan die ster differensiële rotasie,[12] met ’n draaiperiode van sowat 11-13 dae.[9] Geen planete of sirkumstellêre skyf is nog om die ster waargeneem nie.

Verwysings

wysig
  1. ↑ 1,0 1,1 Gray, R. O.; Napier, M. G.; Winkler, L. I. (April 2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars", The Astronomical Journal 121 (4): 2148–2158, doi:10.1086/319956, Bibcode: 2001AJ....121.2148G 
  2. ↑ 2,0 2,1 van Leeuwen, Floor (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V  Nota: Sien VizieR-katalogus I/311.
  3. ↑ 3,0 3,1 3,2 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99), Bibcode: 1966CoLPL...4...99J 
  4. ↑ Holmberg, J. et al. (Julie 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics 501 (3): 941–947, doi:10.1051/0004-6361/200811191, Bibcode: 2009A&A...501..941H. 
  5. ↑ 5,0 5,1 Mallik, Sushma V. (Oktober 1998). "Chromospheric activity in cool stars and the lithium abundance". Astronomy and Astrophysics. 338: 623–636. Bibcode:1998A&A...338..623M.
  6. ↑ Takeda, G.; et al. (2007). "Stellar parameters of nearby cool stars. II. Physical properties of ~1000 cool stars from the SPOCS catalog". Astrophysical Journal Supplement Series. 168: 297–318. arXiv:astro-ph/0607235. Bibcode:2007ApJS..168..297T. doi:10.1086/509763. Nota: Sien VizieR-katalogus J/ApJS/168/297.
  7. ↑ 7,0 7,1 7,2 7,3 Boyajian, Tabetha S. et al. (Februarie 2012), "Stellar Diameters and Temperatures. I. Main-sequence A, F, and G Stars", The Astrophysical Journal 746 (1): 101, doi:10.1088/0004-637X/746/1/101, Bibcode: 2012ApJ...746..101B . Sien tabel 10.
  8. ↑ 8,0 8,1 Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008). "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics". The Astrophysical Journal. 687 (2): 1264–1293. arXiv:0807.1686. Bibcode:2008ApJ...687.1264M. doi:10.1086/591785.
  9. ↑ 9,0 9,1 Gray, David F.; Baliunas, Sallie L. (Januarie 1997), "The Rotation of the G0 Dwarf beta Comae", Astrophysical Journal 475: 303–312, doi:10.1086/303522, Bibcode: 1997ApJ...475..303G 
  10. ↑ "LHS 348 -- High proper-motion Star", SIMBAD (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=Beta+Comae+Berenices, besoek op 2012-02-04 
  11. ↑ "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, archived from the original on 2012-03-10, https://www.webcitation.org/6630AbtJZ?url=http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, besoek op 2012-01-16 
  12. ↑ Donahue, Robert A.; Baliunas, Sallie L. (Julie 1992), "Evidence of differential surface rotation in the solar-type star HD 114710", Astrophysical Journal Letters 393 (2): L63-L66, doi:10.1086/186452, Bibcode: 1992ApJ...393L..63D 

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