Location of Kappa Apodis (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Apus |
| Right ascension | 15 31 30.82213 |
| Declination | −73° 23′ 22.5295″ |
| Apparent magnitude (V) | 5.52 |
| Characteristics | |
| Spectral type | B1npe + sdO |
| U−B color index | −0.791 |
| B−V color index | −0.128 |
| Variable type | γ Cas |
| Astrometry | |
| Radial velocity (Rv) | +62 km/s |
| Proper motion (μ) | RA: +0.996 mas/yr Dec.: −18.345 mas/yr |
| Parallax (π) | 3.0798 ± 0.0717 mas |
| Distance | 1,060 ± 20 ly (325 ± 8 pc) |
| Absolute magnitude (MV) | −2.47 |
| Orbit | |
| 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 | |
| Mass | 11.8±1.0 M☉ |
| Radius | 5.45±0.29 R☉ |
| Luminosity | 2,120 L☉ |
| Surface gravity (log g) | 3.90 cgs |
| Temperature | 21,500 K |
| Rotational velocity (v sin i) | 250 km/s |
| Age | 5.6±1.0 Myr |
| B | |
| Mass | 1.60±0.14 M☉ |
| Radius | 0.44±0.06 R☉ |
| Luminosity | 446 L☉ |
| Temperature | 40,000 K |
| Other designations | |
| κ Aps, CD−72°1139, CPD−72°1802, FK5 567, HD 137387, HIP 76013, HR 5730, SAO 257289 | |
| Database references | |
| SIMBAD | data |
Kappa Apodis, Latinized from κ Apodis, is a binary star 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, 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.
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. The combined spectrum matches a stellar classification of B1npe. 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. Because it is a binary star system, it was most likely not turned into a runaway system as the result of a supernova explosion. A companion star is a 12th magnitude orange K-type subgiant located at an angular separation of 27 arcseconds.
See also
References
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- "HR 5730", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2012-07-08.
- MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, retrieved 8 December 2021.
External links
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