HD 110432
Star in the constellation Crux
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HD 110432 is a Be star in the south-east of Crux, behind the center of the southern hemisphere's dark Coalsack Nebula. It has a stellar classification of B1IVe, which means it is a subgiant star of class B that displays emission lines in its spectrum. This is a variable star of the Gamma Cassiopeiae type, indicating it is a shell star with a circumstellar disk of gas about the equator, and has the variable star designation BZ Crucis. It is not known to be a member of a binary system, although it is probably a member of the open cluster NGC 4609. This star is moderately luminous in the X-ray band, with a variable energy emission of 1032–33 erg s−1 in the range 0.2−12 keV. The X-ray emission may be caused by magnetic activity, or possibly by accretion onto a white dwarf companion.[3]
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Crux |
| Right ascension | 12h 42m 50.2656s[1] |
| Declination | −63° 03′ 31.048″[1] |
| Apparent magnitude (V) | 5.24 - 5.45[2] |
| Characteristics | |
| Spectral type | B1IVe[3] |
| U−B color index | −0.82[4] |
| B−V color index | +0.27[4] |
| Variable type | γ Cas[2] |
| Astrometry | |
| Radial velocity (Rv) | +35[5] km/s |
| Proper motion (μ) | RA: −12.512[1] mas/yr Dec.: −3.984[1] mas/yr |
| Parallax (π) | 2.3834±0.1228 mas[1] |
| Distance | 1,370 ± 70 ly (420 ± 20 pc) |
| Absolute magnitude (MV) | −2.56[6] |
| Details | |
| Mass | 9.6[3] M☉ |
| Radius | 6.5±1.2[7] R☉ |
| Luminosity | 1,153[1] L☉ |
| Surface gravity (log g) | 3.5–3.9[3] cgs |
| Temperature | 22,510–25,000[3] K |
| Rotational velocity (v sin i) | 300–400[3] km/s |
| Other designations | |
| BZ Cru, HR 4830, CD-62 671, HD 110432, GCTP, SAO 252002, FK5 3015, HIP 62027.[8] | |
| Database references | |
| SIMBAD | data |
Distance
The distance of 388 pc published in the 2007 new Hipparcos reduction is over twice the distance of the Coalsack Nebula.[10] The distance from Gaia Data Release 2 is even further at 420 pc.[1]