Beta Circini

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β Circini
Circinus IAU.svg
Red circle.svg

Location of β Circini (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Circinus
Right ascension 15h 17m 30.8494s[1]
Declination −58° 48′ 04.349″[1]
Apparent magnitude (V) 4.069[1]
Spectral type A3 Va[1]
U−B color index +0.09[2]
B−V color index +0.09[2]
Radial velocity (Rv) 9.6 ± 2[1] km/s
Proper motion (μ) RA: −98.39[1] mas/yr
Dec.: −135.46[1] mas/yr
Parallax (π) 33.75 ± 0.75[1] mas
Distance 97 ± 2 ly
(29.6 ± 0.7 pc)
Absolute magnitude (MV) +1.64[3]
Radius 1.3[4] R
Luminosity 19[3] L
Surface gravity (log g) 4.281[5] cgs
Temperature 8,892[5] K
Metallicity [Fe/H] 0.16[3] dex
Rotational velocity (v sin i) 59[2] km/s
Age 166+212
[5] Myr
Other designations
β Cir, Beta Circini, Beta Cir, CPD−58 5875, FK5 561, GC 20526, GJ 580.1, GJ 9516, HD 135379, HIP 74824, HR 5670, PPM 343590, SAO 242384.[1]
Database references

Beta Circini, Latinized from β Circini, is an A-type main sequence star and is the second-brightest star in the constellation of Circinus.[1] It has an apparent visual magnitude of approximately 4.069,[1] which is bright enough to be viewed with the naked eye. Based upon an annual parallax shift of 33.75 mas as seen from the Earth,[1] it is located about 97 light years from the Sun.

With a stellar classification of A3 Va,[1] this is an A-type main-sequence star. It is roughly 166[5] million years old with around 1.3[4] times the Sun's radius. The star is radiating 19[3] times the Sun's luminosity from its photosphere at an effective temperature of 8,892 K.[5] It has one known sub-stellar companion.

Planetary System[edit]

Beta Circini b is a distant brown dwarf companion orbiting the host star at a distance of 6,656 AU.[6][7] It has a surface temperature of 2,084.0 K. Its mass was estimated using the Spectrum method which concluded that the object has a mass of 56.0±7.0 MJ.[6]

The β Circini planetary system[8]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
β Circini b 56.0 (± 7.0) MJ 6656.0


  1. ^ a b c d e f g h i j k l m * bet Cir -- Star, database entry, SIMBAD. Accessed on line September 5, 2008.
  2. ^ a b c HR 5670, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line September 5, 2008.
  3. ^ a b c d Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971Freely accessible, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015. 
  4. ^ a b HD 135379, database entry, Catalog of Apparent Diameters and Absolute Radii of Stars (CADARS), 3rd edition, L. E. Pasinetti-Fracassini, L. Pastori, S. Covino, and A. Pozzi, CDS ID II/224. Accessed on line September 5, 2008.
  5. ^ a b c d e Song, Inseok; et al. (February 2001), "Ages of A-Type Vega-like Stars from uvbyβ Photometry", The Astrophysical Journal, 546 (1): 352–357, arXiv:astro-ph/0010102Freely accessible, Bibcode:2001ApJ...546..352S, doi:10.1086/318269 
  6. ^ a b "β Circini b". Retrieved October 30, 2015. 
  7. ^ Discovery of a brown dwarf companion to the A3V star β Circini. Retrieved November 9, 2015.
  8. ^ "β Circini b". Retrieved 2015-10-30.