Pi Ceti
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cetus |
| Right ascension | 02h 44m 07.348s |
| Declination | −13° 51′ 31.28″ |
| Apparent magnitude (V) | 4.238 |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | B7 V or B7 IV |
| U−B color index | −0.396 |
| B−V color index | −0.130 |
| Astrometry | |
| Radial velocity (Rv) | 14.98±0.25 km/s |
| Proper motion (μ) | RA: −8.394 mas/yr Dec.: −23.592 mas/yr |
| Parallax (π) | 8.4022±0.1945 mas |
| Distance | 388 ± 9 ly (119 ± 3 pc) |
| Absolute magnitude (MV) | −1.16 |
| Orbit | |
| Period (P) | 2,722±14 d |
| Eccentricity (e) | 0.00±0.07 |
| 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 a binary star system in the equatorial constellation of Cetus. Its name is a Bayer designation that is Latinized from π Ceti, and abbreviated Pi Cet or π Cet. The system is located near the eastern boundary of the constellation and is sometimes portrayed as forming part of the Eridanus constellation's asterism. It is visible to the naked eye as a point of light with an apparent visual magnitude of 4.238. Observed to have a half yearly parallax shift of 8.30 mas as seen from Earth, it is located at a distance of approximately 393 light years from the Sun. The system is drifting further away from the Sun with a line of sight velocity component of +15 km/s.
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.