Pi Pavonis
  | |
| 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 |
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]
The primary component is an chemically peculiar star that displays an abundance anomaly of strontium.[11][12] Grey et al. (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 a more distant 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]
References
[edit]- ^ a b c d e f Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600. Vizier catalog entry
- ^ a b c Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644. Vizier catalog entry
- ^ a b Gray, R. O.; Garrison, R. F. (1989). "The early F-type stars - Refined classification, confrontation with Stromgren photometry, and the effects of rotation". Astrophysical Journal Supplement Series. 69: 301. Bibcode:1989ApJS...69..301G. doi:10.1086/191315.
- ^ a b c d e f g h Waisberg, Idel; Klein, Ygal; Katz, Boaz (2023-07-04). "Hidden Companions to Intermediate-mass Stars. VII. Discovery of a 0.76 M☉, 39 au Companion to the Ap Star HIP 88866 = π Pavonis". Research Notes of the AAS. 7 (7): 138. Bibcode:2023RNAAS...7..138W. doi:10.3847/2515-5172/ace2be. ISSN 2515-5172.
- ^ a b Mermilliod, J. C. (2006). "VizieR Online Data Catalog: Homogeneous Means in the UBV System (Mermilliod 1991)". VizieR On-line Data Catalog: II/168. Originally Published in: Institut d'Astronomie. 2168. Bibcode:2006yCat.2168....0M.Vizier catalog entry
- ^ a b Wilson, R. E. (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W. LCCN 54001336.
- ^ a b Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b Erspamer, D.; North, P. (February 2003). "Automated spectroscopic abundances of A and F-type stars using echelle spectrographs. II. Abundances of 140 A-F stars from ELODIE". Astronomy and Astrophysics. 398 (3): 1121–1135. arXiv:astro-ph/0210065. Bibcode:2003A&A...398.1121E. doi:10.1051/0004-6361:20021711. S2CID 1109164.
- ^ Glebocki, R.; Gnacinski, P. (2005). "VizieR Online Data Catalog: Catalog of Stellar Rotational Velocities (Glebocki+ 2005)". VizieR On-line Data Catalog: III/244. Originally Published in: 2005csss...13..571G; 2005yCat.3244....0G. 3244. Bibcode:2005yCat.3244....0G. Vizier catalog entry
- ^ "pi Pav". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-12.
- ^ a b Loden, L. O.; Sundman, A. (June 1989). "Giant CP stars?". Journal of Astrophysics and Astronomy. 10 (2): 183–196. Bibcode:1989JApA...10..183L. doi:10.1007/BF02719315. S2CID 121258394.
- ^ Renson, P.; Manfroid, J. (2009). "Catalogue of Ap, Hg Mn and Am stars". Astronomy and Astrophysics. 498 (3): 961. Bibcode:2009A&A...498..961R. doi:10.1051/0004-6361/200810788.
