Kappa1 Apodis

Kappa1 Apodis
Location of Kappa1 Apodis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Apus
Right ascension 15h 31m 30.82213s[1]
Declination −73° 23′ 22.5295″[1]
Apparent magnitude (V) 5.52[2]
Characteristics
Spectral type B1npe[3] + sdO[4]
U−B color index −0.791[2]
B−V color index −0.128[2]
Variable type γ Cas[5]
Astrometry
Radial velocity (Rv)+62[6] km/s
Proper motion (μ) RA: +0.996[1] mas/yr
Dec.: −18.345[1] mas/yr
Parallax (π)3.0798 ± 0.0717 mas[1]
Distance1,060 ± 20 ly
(325 ± 8 pc)
Absolute magnitude (MV)−2.47[7]
Orbit[8]
Period (P)192.1 ± 0.1 d
Inclination (i)60 ± 4°
Periastron epoch (T)HJD 2458401.9 ± 2.2
Semi-amplitude (K1)
(primary)		9.09 ± 0.08 km/s
Semi-amplitude (K2)
(secondary)		66.87 ± 1.84 km/s
Details
A
Mass11.8±1.0[8] M☉
Radius5.45±0.29[4] R☉
Luminosity2,120[7] L☉
Surface gravity (log g)3.90[9] cgs
Temperature21,500[9] K
Rotational velocity (v sin i)250[4] km/s
Age5.6±1.0[10] Myr
B
Mass1.60±0.14[8] M☉
Radius0.44±0.06[4] R☉
Luminosity446[4] L☉
Temperature40,000[4] K
Other designations
κ1 Aps, CD−72°1139, CPD−72°1802, FK5 567, HD 137387, HIP 76013, HR 5730, SAO 257289[11]
Database references
SIMBADdata

Kappa1 Apodis, Latinized from κ1 Apodis, is a binary star[3] system in the southern circumpolar constellation of Apus. Based upon parallax measurements, it is located roughly 1,060 light-years (325 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.[6]

A light curve for Kappa1 Apodis, plotted from TESS data[12]

This is a spectroscopic binary system, made up of a Be star and a subdwarf O star, which complete an orbit around each other every 192 days.[8] 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.[10] 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.

See also

References

  1. ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b c d 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. ^ a b c d 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. ^ a b c d e f Wang, Luqian; Gies, Douglas R.; Peters, Geraldine J.; Götberg, Ylva; Chojnowski, S. Drew; Lester, Kathryn V.; Howell, Steve B. (2021). "The Detection and Characterization of Be+sdO Binaries from HST/STIS FUV Spectroscopy". The Astronomical Journal. 161 (5): 248. arXiv:2103.13642. Bibcode:2021AJ....161..248W. doi:10.3847/1538-3881/abf144.
  5. ^ 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.
  6. ^ a b Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick (eds.), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E.
  7. ^ a b 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.
  8. ^ a b c d Wang, Luqian; Gies, Douglas R.; Peters, Geraldine J.; Han, Zhanwen (April 2023). "The Orbital and Physical Properties of Five Southern Be+sdO Binary Systems". The Astronomical Journal. 165 (5): 203. arXiv:2303.12616. Bibcode:2023AJ....165..203W. doi:10.3847/1538-3881/acc6ca. ISSN 1538-3881.
  9. ^ a b 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, S2CID 118362423.
  10. ^ a b 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, S2CID 118629873.
  11. ^ "HR 5730", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2012-07-08.
  12. ^ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, retrieved 8 December 2021.