Pi Pavonis
Binary star in the constellation Pavo
From Wikipedia, the free encyclopedia
π Pavonis, Latinized as Pi Pavonis, is a binary star[4] in the constellation Pavo. It is a white-hued star that is visible to the naked eye as a faint point of light with an apparent visual magnitude of 4.33.[2] The distance to this object is 130 light years based on parallax,[1] but it is drifting closer to the Sun with a radial velocity of −15.6 km/s.[6]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Pavo |
| Right ascension | 18h 08m 34.81459s[1] |
| Declination | −63° 40′ 06.7906″[1] |
| Apparent magnitude (V) | 4.33[2] |
| Characteristics | |
| Spectral type | kA4hF0mF2 III[3] + KV[4] |
| U−B color index | +0.17[5] |
| B−V color index | +0.23[5] |
| Astrometry | |
| Radial velocity (Rv) | −15.60[6] km/s |
| Proper motion (μ) | RA: +18.02[1] mas/yr Dec.: -207.57[1] mas/yr |
| Parallax (π) | 25.09±0.17 mas[1] |
| Distance | 130.0 ± 0.9 ly (39.9 ± 0.3 pc) |
| Absolute magnitude (MV) | 1.33[2] |
| Details[4] | |
| A | |
| Mass | 1.80 M☉ |
| Radius | 2.80 R☉ |
| Luminosity | 24.69±0.36[7] L☉ |
| Surface gravity (log g) | 3.81[8] cgs |
| Temperature | 7,560 K |
| Metallicity [Fe/H] | 0.27[8] dex |
| Rotational velocity (v sin i) | 30.0[9] km/s |
| Age | 1.4 Gyr |
| B | |
| Mass | 0.76 M☉ |
| Radius | 0.70 R☉ |
| Temperature | 4,710 K |
| Position (relative to A)[4] | |
| Component | B |
| Angular distance | 959 mas |
| Projected separation | 39.3 AU |
| Other designations | |
| π Pav, CPD−63°4292, FK5 3437, GC 24665, HD 165040, HIP 88866, HR 6745, SAO 254147[10] | |
| Database references | |
| SIMBAD | data |
The primary component is an chemically peculiar star that displays an abundance anomaly of strontium.[11][12] Gray & Garrison (1989) classify it as kA4hF0mF2 III,[3] matching a giant Am star with the calcium K line of an A4 star, the hydrogen lines of a cooler F0 star, and the metal lines of a F2 star. However, Loden and Sundman (1989) don't consider it to be a giant and list it as an Ap star.[11] It is 1.4 billion years old with 1.8 times the mass of the Sun and 2.8 times the Sun's radius.[4] The star is radiating 24.7[7] times the Sun's luminosity from its photosphere at an effective temperature of 7,560 K.[4]
The secondary is a K-type main-sequence star, much smaller than its primary, at 0.76 solar masses and 0.7 solar radii. It has an effective temperature 4,710 K and is 3.63 magnitudes fainter than the primary in the H band. They are separated by 39.3 astronomical units and have an estimated orbital period of 150 years.[4]
There is evidence for another companion using Hipparcos-Gaia astrometry, which should be a star with less than 0.7 times the mass of the Sun, closer to the primary star.[4]