QZ Puppis
Star in the constellation Puppis
From Wikipedia, the free encyclopedia
QZ Puppis (QZ Pup, b Pup) is a class B2.5V (blue main-sequence) star in the constellation Puppis. Its apparent magnitude is 4.5 and it is approximately 650 light years away based on parallax.
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Puppis |
| Right ascension | 07h 52m 38.64663s[1] |
| Declination | −38° 51′ 46.1305″[1] |
| Apparent magnitude (V) | 4.47 - 4.54[2] |
| Characteristics | |
| Spectral type | B2.5V[3] |
| U−B color index | −0.68[4] |
| B−V color index | -0.20[4] |
| Variable type | ellipsoidal[2] |
| Astrometry | |
| Radial velocity (Rv) | +29.50[5] km/s |
| Proper motion (μ) | RA: −8.92[1] mas/yr Dec.: +3.34[1] mas/yr |
| Parallax (π) | 5.03±0.19 mas[1] |
| Distance | 650 ± 20 ly (199 ± 8 pc) |
| Absolute magnitude (MV) | −2.00[6] |
| Details | |
| Mass | 6.0[7] M☉ |
| Radius | 7.3[7] R☉ |
| Luminosity | 2,268[7] L☉ |
| Surface gravity (log g) | 3.5[7] cgs |
| Temperature | 15,254[7] K |
| Metallicity [Fe/H] | −0.15[8] dex |
| Rotational velocity (v sin i) | 151[9] km/s |
| Age | 24.1[10] Myr |
| Other designations | |
| b Puppis, QZ Pup, CD−38°3769, GC 10661, GSC 07646-03591, HIP 38455, HR 3084, HD 64503, NSV 3789, SAO 198545 | |
| Database references | |
| SIMBAD | data |
QZ Puppis was identified as a small-amplitude variable star in 1974, but the nature of the variability was unclear. It was thought to be a spectroscopic binary on the basis of variability in the radial velocity of its spectral lines.[12] As a hot B-class main sequence star with variable spectral lines, it was suspected of being a β Cephei variable but this classification was repeatedly rejected.[13] The short-period sinusoidal variations in brightness with an amplitude of 0.03 magnitudes were interpreted as ellipsoidal variations as the star, distorted by a close companion, rotates with a period of 1.1 days.[12] Later analysis of Hipparcos photometry detected shallow eclipses.[14]
The companion to QZ Puppis is only known from its effect on the visible star as they orbit. The primary shows radial velocity variations of 71 km/s as it orbits every 1.112 days.