Binary star in the constellation Pavo
π Pavonis , Latinized as Pi Pavonis , is a binary star [ 4] 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] light years based on parallax ,[ 1] 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] [ 3] 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] mass of the Sun and 2.8 times the Sun's radius .[ 4] [ 7] 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]
References
^ 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
