NW Puppis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Puppis |
| Right ascension | 07h 18m 38.18632s |
| Declination | −36° 44′ 33.8557″ |
| Apparent magnitude (V) | 5.11 |
| Characteristics | |
| Spectral type | B3 Vne |
| Variable type | β Cep |
| Astrometry | |
| Radial velocity (Rv) | +18.00±10 km/s |
| Proper motion (μ) | RA: −10.848 mas/yr Dec.: +6.699 mas/yr |
| Parallax (π) | 3.5875±0.1683 mas |
| Distance | 910 ± 40 ly (280 ± 10 pc) |
| Details | |
| Mass | 6.5 M☉ |
| Radius | 5.6 R☉ |
| Luminosity | 1,995 L☉ |
| Surface gravity (log g) | 4.07±0.57 cgs |
| Temperature | 17,930±540 K |
| Rotation | 1.42 days |
| Rotational velocity (v sin i) | 80±8 km/s |
| Age | 40 Myr |
| Other designations | |
| υ2 Pup, NW Pup, CD−36°3519, HD 57219, HIP 35406, HR 2790, SAO 197837, NW Puppis, υ2 Puppis, Upsilon2 Puppis, Upsilon2 Pup | |
| Database references | |
| SIMBAD | data |
NW Puppis, also known as υ2 Puppis, is a star in the constellation Puppis. Located around 910 light-years distant, it shines with a luminosity approximately 2,000 times that of the Sun and has a surface temperature of 17,930 K.
The star's variability was first detected in 1970 (based on observations made at La Silla Observatory), and announced by Armand van Hoof in 1973. It was given its variable star designation in 1977. Anamarija Stankov ruled this star out as a Beta Cephei variable, but the GCVS and the International Variable Star Index classify it as both a Beta Cephei variable and a rotating ellipsoidal variable. The GCVS lists its period as 0.125 days, but the TESS data shows lower frequency and stochastic brightness variations.
Neither component of this double is given a letter in Lacaille's catalogue or the British Association star catalogue. Gould gave them the designations (Latin letter) v1 and v2 Puppis, but these are rarely used. Lacaille applied the Greek letter υ to the star now called υ Carinae. The designation υ2 first appeared in several catalogues at the end of the 19th century.