  | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Circinus |
| Right ascension | 15h 17m 30.84945s[1] |
| Declination | −58° 48′ 04.3453″[1] |
| Apparent magnitude (V) | 4.069[2] |
| Characteristics | |
| Spectral type | A3 Va[2] |
| U−Bcolor index | +0.09[3] |
| B−Vcolor index | +0.09[3] |
| Astrometry | |
| Radial velocity (Rv) | 9.6±2[2] km/s |
| Proper motion (μ) | RA: −97.182[1]mas/yr Dec.: −136.055[1]mas/yr |
| Parallax (π) | 35.8205±0.2515 mas[1] |
| Distance | 91.1 ± 0.6 ly (27.9 ± 0.2 pc) |
| Absolute magnitude (MV) | +1.64[4] |
| Details | |
| Mass | 1.96+0.03 −0.01[5] M☉ |
| Radius | 1.92[6] R☉ |
| Luminosity | 19[4] L☉ |
| Surface gravity (log g) | 4.281[7] cgs |
| Temperature | 8676±33[5] K |
| Metallicity[Fe/H] | 0.16[4] dex |
| Rotational velocity (v sin i) | 59[3] km/s |
| Age | 370–500[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.[2] | |
| Database references | |
| SIMBAD | data |
Beta Circini,Latinized fromβ Circini, is anA-typemain sequencestar and is the second-brightest star in theconstellation ofCircinus.[2] It has anapparent visual magnitude of approximately 4.069,[2] which is bright enough to be viewed with the naked eye. Based upon an annualparallax shift of35.8 mas as seen from the Earth, it is located 91 light years from theSun.
With astellar classification of A3 Va,[2] this is anmain-sequence star fusing atoms ofhydrogen intohelium at its core. It is between 370 and 500 million years old[5] with around 1.9[6] times theSun's radius. The star is radiating 19[4] times theSun's luminosity from itsphotosphere at aneffective temperature of 8,676 K.[5] It has one known sub-stellar companion.
Beta Circini b is a distantbrown dwarf companion orbiting the host star at a distance of 6,656 AU. It was detected as aproper motion companion to Beta Circini in 2015 by L.C. Smith and collaborators. Using BHAC15 isochrones, its mass is estimated at 0.056 M☉, or59 MJ. It has astellar classification of L1 and a temperature of 2,084 K (1,811 °C).[5]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 58.7±7.3 MJ | 6,656 | — | — | — | — |
