| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Octans |
| Right ascension | 14h 35m 29.6633s[2] |
| Declination | −89° 46′ 18.176″[2] |
| Apparent magnitude (V) | 6.66 - 7.06[3] |
| Characteristics | |
| Evolutionary stage | S5,1[4] |
| Variable type | SRb[3] |
| Astrometry | |
| Radial velocity (Rv) | −3.5[5] km/s |
| Proper motion (μ) | RA: −8.022[2]mas/yr Dec.: −8.668[2]mas/yr |
| Parallax (π) | 1.8237±0.0296 mas[2] |
| Distance | 1,790 ± 30 ly (548 ± 9 pc) |
| Details | |
| Mass | 2.7[6] M☉ |
| Radius | 197[7] R☉ |
| Luminosity | 3,767[8] L☉ |
| Surface gravity (log g) | 0.31[6] cgs |
| Temperature | 3,520[8] K |
| Metallicity [Fe/H] | +0.10[6] dex |
| Other designations | |
| CD−89°10,FK5 3985,HD 110994,HIP 71348,SAO 258660[9] | |
| Database references | |
| SIMBAD | data |
BQ Octantis (BQ Oct) is avariable star in theconstellationOctans. It is anS-type star with anapparent magnitude of 6.82. It lies less than a quarter degree from theSouth Celestial Pole (SCP), making it the closest star to the SCP brighter than magnitude 7. While it is much nearer the pole thanPolaris Australis (the star commonly used as the southpole star), it is too dim to thenaked eye to use as a visual reference.
BQ Octantis is ared giant on theasymptotic giant branch. Itsspectrum has been classified as M3III or M4III.[10] The spectrum shows abnormal abundances ofs-process elements and particularly ZrO, so it is classified as an S star. These stars havedredged up fusion products from the interior, especially carbon. They have reached approximately equal levels of carbon and oxygen in their atmospheres, which causes dramatic changes to the atmospheric chemistry which are visible in the spectrum. As an S star, its spectrum is classified as S5,1, with S5 approximately equivalent to the temperature of an M5 giant and the 1 indicating that the ZrO bands are relatively weak.[4]
BQ Octantis is a variable star. An amplitude of 0.05 magnitudes about anapparent magnitude of 6.82 has been derived fromHipparcos satellitephotometry. The same photometry found a possible period of0.82 d but this was very uncertain and no variability type could be determined.[11] It is listed in theGeneral Catalogue of Variable Stars as a possibleslow irregular variable.[12] It was classified as a variable star in 1977,[13] on the basis of a 1960 study.[14]All Sky Automated Survey data shows a period of 48.1 days[3]
