Kappa2 Apodis
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Apus[1] |
| Right ascension | 15h 40m 21.355s[2] |
| Declination | –73° 26′ 48.00″[2] |
| Apparent magnitude (V) | 5.65[3] |
| Characteristics | |
| Spectral type | B7 III-IV + K0 V[4] |
| U−B color index | –0.38[3] |
| B−V color index | –0.04[3] |
| Astrometry | |
| Radial velocity (Rv) | –19.0[5] km/s |
| Proper motion (μ) | RA: –15.517 mas/yr[2] Dec.: –26.408 mas/yr[2] |
| Parallax (π) | 4.5583±0.0823 mas[2] |
| Distance | 720 ± 10 ly (219 ± 4 pc) |
| Absolute magnitude (MV) | −1.24[1] + 6.50[6] |
| Details | |
| κ2 Aps A | |
| Mass | 4.995±0.250[7] M☉ |
| Radius | 5.555±0.278[7] R☉ |
| Luminosity | 316[8] L☉ |
| Surface gravity (log g) | 3.86[8] cgs |
| Temperature | 12,646[8] K |
| Age | 130[8] Myr |
| κ2 Aps C[8] | |
| Luminosity | 0.25[6] L☉ |
| Temperature | 5,127[6] K |
| Other designations | |
| κ2 Apodis, Kap2 Aps, κ2 Aps, CPD–73° 1625, HD 138800, HIP 76750, HR 5782, SAO 257307[9] | |
| Database references | |
| SIMBAD | data |
Kappa2 Apodis is a double star in the southern circumpolar constellation of Apus. Its identifier is a Bayer designation that is Latinized from κ2 Apodis, and abbreviated Kap2 Aps or κ2 Aps, respectively. This star is located at a distance of approximately 720 light-years (220 parsecs) from Earth, based upon parallax measurements with a 1.4% margin of error.[2] They are approaching the Sun with a radial velocity of −19 km/s.[5] The pair have a combined apparent visual magnitude of +5.65,[3] which makes the system faintly visible to the naked eye.
The brighter star, designated κ2 Aps A, has a stellar classification of B7 III-IV, with the luminosity class of III-IV suggesting that it may lie in an intermediate stage between a subgiant and a giant star.[10] Based on observations with TESS, it is a pulsating B star of the Maia type.[11] This star is about 130[8] million years old with an estimated 5 times the mass and 5.6 times the radius of the Sun.[7] It is radiating 316[8] times the luminosity of the Sun from its photosphere at an effective temperature of 12,646 K.[8]
A faint companion, κ2 Aps C,[8] is a K-type main sequence star with a classification of K0 V. It has a visual magnitude of 12.5 and an angular separation of 15 arcseconds from the brighter member.[4] The pair have a projected separation of around 2,520 au.[6]
References
[edit]- ^ 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.
- ^ 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.
- ^ a b c d Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
- ^ a b Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ a b Wilson, Ralph Elmer (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication, Washington: Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
- ^ a b c d Lindroos, K. P. (May 1985), "A study of visual double stars with early type primaries. IV. Astrophysical data", Astronomy and Astrophysics, 60: 183–221, Bibcode:1985A&AS...60..183L.
- ^ a b c Kervella, Pierre; et al. (March 2019), "Stellar and substellar companions of nearby stars from Gaia DR2. Binarity from proper motion anomaly", Astronomy & Astrophysics, 623: 23, arXiv:1811.08902, Bibcode:2019A&A...623A..72K, doi:10.1051/0004-6361/201834371, S2CID 119491061, A72.
- ^ a b c d e f g h i Gerbaldi, M.; et al. (2001), "Binary systems with post-T Tauri secondaries", Astronomy & Astrophysics, 379 (1): 162–184, Bibcode:2001A&A...379..162G, doi:10.1051/0004-6361:20011298, ISSN 0004-6361.
- ^ "HR 5782", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2012-07-10.
- ^ Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 1, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1975mcts.book.....H.
- ^ Balona, L. A.; Ozuyar, D. (2020), "Pulsation among TESS a and B stars and the Maia variables", Monthly Notices of the Royal Astronomical Society, 493 (4): 5871, arXiv:2001.04497, Bibcode:2020MNRAS.493.5871B, doi:10.1093/mnras/staa670, S2CID 210472317.
