Kappa Pyxidis

Kappa Pyxidis, Latinized from κ Pyxidis, is a single,[8] orange-hued star in the southern constellation of Pyxis. It is visible to the naked eye as a faint point of light with an apparent visual magnitude of +4.62.[2] The star is located approximately 520 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −45 km/s[5] and may come as close as 308 light-years in around 2.6 million years. It is moving through space at the rate of 53.7 km/s relative to the Sun and is following an orbit through the Milky Way galaxy with a large eccentricity of 0.68[2]

κ Pyxidis
Location of κ Pyxidis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Pyxis
Right ascension  09h 08m 02.88015s[1]
Declination –25° 51′ 30.7331″[1]
Apparent magnitude (V) 4.62[2]
Characteristics
Spectral type K4III[3]
U−B color index +1.87[4]
B−V color index +1.594±0.004[2]
Astrometry
Radial velocity (Rv)−44.7±2.8[5] km/s
Proper motion (μ) RA: +34.771[1] mas/yr
Dec.: +0.009[1] mas/yr
Parallax (π)6.3116 ± 0.2408[1] mas
Distance520 ± 20 ly
(158 ± 6 pc)
Absolute magnitude (MV)−1.53[2]
Details
Radius66.70+0.34
−2.34[1] R☉
Luminosity927±40[1] L☉
Surface gravity (log g)1.44±0.22[6] cgs
Temperature3,931±31[6] K
Metallicity [Fe/H]−0.22±0.08[6] dex
Other designations
κ Pyx, CPD−25°4067, GC 12614, HD 78541, HIP 44824, HR 3628, SAO 177002, PPM 255695, CCDM J09080-2552AB, WDS J09080-2552AB[7]
Database references
SIMBADdata

This is an aging giant with a stellar classification of K4III,[3] having exhausted the supply of hydrogen at its core then expanded and cooled. At present it has 67[1] times the radius of the Sun. It is a variable star of uncertain type, changing brightness with an amplitude of 0.0058 in visual magnitude over a period of 8.5 days.[9] The star radiates 927 times the luminosity of the Sun from its bloated photosphere at an effective temperature of 3,931 K.[6] A magnitude 10 visual companion is located at an angular separation of 2.1 arcseconds.[10]

References
  1. 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.
  2. 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.
  3. Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins Catalog of Revised MK Types for the Cooler Stars", The Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
  4. Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99), Bibcode:1966CoLPL...4...99J.
  5. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
  6. Prugniel, Ph.; et al. (July 2011), "The atmospheric parameters and spectral interpolator for the MILES stars", Astronomy & Astrophysics, 531: A165, arXiv:1104.4952, Bibcode:2011A&A...531A.165P, doi:10.1051/0004-6361/201116769.
  7. "kap Pyx". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-14.
  8. Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  9. Koen, Chris; Eyer, Laurent (2002), "New periodic variables from the Hipparcos epoch photometry", Monthly Notices of the Royal Astronomical Society, 331: 45, arXiv:astro-ph/0112194, Bibcode:2002MNRAS.331...45K, doi:10.1046/j.1365-8711.2002.05150.x.
  10. Privett, Grant; Jones, Kevin (2013), The Constellation Observing Atlas, New York, New York: Springer Science & Business Media, p. 168, ISBN 9781461476481.
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