Pi Ceti
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cetus |
| Right ascension | 02h 44m 07.34928s |
| Declination | −13° 51′ 31.3130″ |
| Apparent magnitude (V) | 4.238 |
| Characteristics | |
| Spectral type | B7 V or B7 IV |
| U−B color index | −0.396 |
| B−V color index | −0.130 |
| Astrometry | |
| Proper motion (μ) | RA: −8.62 mas/yr Dec.: −9.07 mas/yr |
| Parallax (π) | 8.30±0.21 mas |
| Distance | 393 ± 10 ly (120 ± 3 pc) |
| Absolute magnitude (MV) | −1.16 |
| Orbit | |
| Period (P) | 2,722±14 d |
| Eccentricity (e) | 0.0±0.7 |
| Periastron epoch (T) | 2444852 ± 29 JD |
| Argument of periastron (ω) (secondary) | 0.0° |
| Semi-amplitude (K1) (primary) | 4.33±0.25 km/s |
| Details | |
| π Cet A | |
| Mass | 4.4±0.2 M☉ |
| Radius | 4.3±0.3 R☉ |
| Luminosity | 468 L☉ |
| Surface gravity (log g) | 3.8±0.2 cgs |
| Temperature | 12,900±400 K |
| Metallicity [Fe/H] | 0.28±0.16 dex |
| Rotational velocity (v sin i) | 20.9±1.2 km/s |
| Age | 0.3+0.1 −0.1 Myr |
| Other designations | |
| π Cet, 89 Ceti, BD−14 519, FK5 97, HD 17081, HIP 12770, HR 811, SAO 148575. | |
| Database references | |
| SIMBAD | data |
Pi Ceti, Latinized from π Ceti, is the Bayer designation for a star system in the equatorial constellation of Cetus. It is visible to the naked eye with an apparent visual magnitude of 4.238. Observed to have an Earth half yearly parallax shift of 8.30 mas, it is around 393 light years from the Sun.
This is a single-lined spectroscopic binary system with a nearly circular orbit and a period of 7.45 years. The fact that the system has a negligible eccentricity is surprising for such a long period, and may suggest that the secondary is a white dwarf that had its orbit circularized during a mass-transfer event.
The primary, component A, is a normal B-type star that has been given stellar classifications of B7 V and B7 IV. It appears very young – less than half a million years in age – and may still be on a pre-main sequence track. The star shows no magnetic field but it does emit an infrared excess.