Kappa1 Apodis

Kappa1 Apodis, Latinized from κ1 Apodis, is the Bayer designation for a binary star[3] system in the southern circumpolar constellation of Apus. Based upon parallax measurements, it is located roughly 1,200 light-years (370 parsecs) from Earth. The combined apparent visual magnitude of the system is 5.52,[2] indicating that this is a faint, naked eye star that can be viewed in dark suburban skies. It is moving away from the Sun with a radial velocity of +62 km/s.[5]

For other stars with this Bayer designation, see κ Apodis.
Kappa1 Apodis
Location of κ1 Apodis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Apus
Right ascension  15h 31m 30.82178s[1]
Declination −73° 23′ 22.5291″[1]
Apparent magnitude (V) 5.52[2]
Characteristics
Spectral type B1npe[3]
U−B color index -0.791[2]
B−V color index -0.128[2]
Variable type γ Cas[4]
Astrometry
Radial velocity (Rv)+62[5] km/s
Proper motion (μ) RA: +0.56[1] mas/yr
Dec.: -18.40[1] mas/yr
Parallax (π)2.63 ± 0.27[1] mas
Distanceapprox. 1,200 ly
(approx. 380 pc)
Absolute magnitude (MV)−2.47[6]
Details
Mass12.0 ± 0.3[7] M☉
Luminosity2,120[6] L☉
Surface gravity (log g)3.90[8] cgs
Temperature21,500[8] K
Age5.6 ± 1.0[7] Myr
Other designations
κ1 Aps, CD−72° 1139, CPD−72° 1802, FK5 567, HD 137387, HIP 76013, HR 5730, SAO 257289[9]
Database references
SIMBADdata

This is a spectroscopic binary system with an orbital period of 0.6 days.[3] The combined spectrum matches a stellar classification of B1npe.[3] The 'e' suffix indicates that this is a Be star with emission lines in the spectrum. An 'n' means that the absorption lines in the spectrum are broadened from the Doppler effect as a result of rapid rotation. Finally, the 'p' shows some peculiarity in the spectrum. It is classified as a Gamma Cassiopeiae type variable star and its brightness varies from magnitude +5.43 to +5.61.

This is a runaway star with a peculiar velocity of 69.8 ± 4.7 km/s.[7] Because it is a binary star system, it was most likely not turned into a runaway system as the result of a supernova explosion.[3] A companion star is a 12th magnitude orange K-type subgiant located at an angular separation of 27 arcseconds.

References
  1. van Leeuwen, F. (November 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.
  2. Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", Astrophysical Journal Supplement, 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168.
  3. Jilinski, E.; et al. (September 2010), "A Dynamical Study of Suspected Runaway Stars as Traces of Past Supernova Explosions in the Region of the Scorpius-Centaurus OB Association", The Astrophysical Journal, 721 (1): 469–477, Bibcode:2010ApJ...721..469J, doi:10.1088/0004-637X/721/1/469.
  4. Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007–2013)". VizieR On-line Data Catalog: B/gcvs. 1: 02025. Bibcode:2009yCat....102025S.
  5. Evans, D. S. (June 20–24, 1966), Batten, Alan Henry; Heard, John Frederick (eds.), The Revision of the General Catalogue of Radial Velocities, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E.
  6. 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.
  7. Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x.
  8. Soubiran, C.; Le Campion, J.-F.; Cayrel de Strobel, G.; Caillo, A. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv:1004.1069, Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247.
  9. "HR 5730". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-07-08.
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