Zeta Puppis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Puppis |
| Right ascension | 08h 03m 35.05s |
| Declination | −40° 00′ 11.3″ |
| Apparent magnitude (V) | 2.24 - 2.26 |
| Characteristics | |
| Evolutionary stage | Blue supergiant |
| Spectral type | O4If(n)p |
| U−B color index | −1.09 |
| B−V color index | −0.27 |
| Variable type | rotating? |
| Astrometry | |
| Proper motion (μ) | RA: −29.71 mas/yr Dec.: 16.68 mas/yr |
| Parallax (π) | 3.01±0.10 mas |
| Distance | 1,080 ± 40 ly (330 ± 10 pc) |
| Absolute magnitude (MV) | −6.23 |
| Details | |
| Mass | 25.3±5.3 M☉ |
| Radius | 13.72±0.49 (equatorial) R☉ 11.25±0.19 (polar) R☉ |
| Luminosity (bolometric) | 446,700+66,200 −57,600 L☉ |
| Surface gravity (log g) | 3.52±0.08 cgs |
| Temperature | 40,000 K |
| Metallicity [Fe/H] | 0.34 dex |
| Rotation | 1.78 days |
| Rotational velocity (v sin i) | >220 km/s |
| Age | 2.2+0.6 −0.5 to 3.56+0.77 −0.75 Myr |
| Other designations | |
| Naos, Suhail Hadar, ζ Puppis, ζ Pup, Zeta Pup, CPD−39°2011, FK5 306, GC 10947, HD 66811, HIP 39429, HR 3165, PPM 312524, SAO 198752. | |
| Database references | |
| SIMBAD | data |
Zeta Puppis (ζ Puppis, abbreviated Zeta Pup, ζ Pup), formally named Naos /naʊs/, is the brightest star in the constellation of Puppis.
The spectral class of O4 means this is one of the hottest, and most luminous, stars visible to the naked eye. It is one of the sky's few naked-eye class O-type stars as well as one of the closest to Earth. It is a blue supergiant, one of the most luminous stars in the Milky Way. Visually it is over 10,000 times brighter than the Sun, but its high temperature means that most of its radiation is in the ultraviolet and its bolometric luminosity is over 500,000 times that of the Sun. It is also the 72nd brightest star in terms of apparent magnitude from Earth. It is a runaway star, meaning it has an unusually large space velocity, probably caused by being ejected from a close binary system when its companion exploded as a supernova.
Zeta Puppis is typical of O-type stars in having an extremely strong stellar wind, measured at 2,500 km/s, which sees the star shed more than a millionth of its mass each year, or about 10 million times that shed by the Sun over a comparable time period.