BP Circini

BP Circini is a binary star system in the southern constellation of Circinus. It is located at a distance of approximately 3,300 light years from the Sun based on parallax.^[2]

BP Circini

A light curve for BP Circini, plotted from Hipparcos data[1]
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Circinus
Right ascension	14h 46m 41.98011s[2]
Declination	−61° 27′ 42.9903″[2]
Apparent magnitude (V)	7.37 - 7.71[3]
Characteristics
Spectral type	F2/3II + B6V[4]
B−V color index	0.649±0.020[5]
Astrometry
Proper motion (μ)	RA: −5.355[2] mas/yr Dec.: −3.920[2] mas/yr
Parallax (π)	0.9952±0.0402 mas[2]
Distance	3,300 ± 100 ly (1,000 ± 40 pc)
Absolute magnitude (MV)	−2.91[6]
Orbit[6]
Period (P)	20 yr
Semi-major axis (a)	15.8 AU
Details
A
Mass	5[7] M☉
Radius	30.38+6.93 −6.50[2] R☉
Luminosity	917±54[2] L☉
Surface gravity (log g)	2.75[8] cgs
Temperature	6356±23[8] K
B
Mass	4.7[6] M☉
Surface gravity (log g)	4.0±0.5[7] cgs
Temperature	16,000±1,000[7] K
Other designations
BP Cir, CD−60°5320, HD 129708, HIP 72264, SAO 252879, WDS J14467-6128A[9]
Database references
SIMBAD	data

The variability of this star was discovered by D. W. Kurtz in 1979.^[7] A small-amplitude Cepheid variable,^[8] its apparent magnitude ranges from 7.37 to 7.71 over 2.39810 days.^[3] A spectroscopic binary, the primary is a yellow-white bright giant of spectral type F2 or F3II.^[4] The spectrum shows peculiarities in the metallic lines.^[10] The secondary is a 4.7 solar mass (M_☉) blue-white main sequence star of spectral type B6.^[6]