Delta Apodis
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Apus |
| δ1 Aps | |
| Right ascension | 16h 20m 20.80462s[1] |
| Declination | −78° 41′ 44.6889″[1] |
| Apparent magnitude (V) | +4.66 - 4.87[2] |
| δ2 Aps | |
| Right ascension | 16h 20m 26.85843s[1] |
| Declination | −78° 40′ 02.9901″[1] |
| Apparent magnitude (V) | +5.27[3] |
| Characteristics | |
| Spectral type | M5 IIIb + K3 III[4] |
| U−B color index | +1.68/+1.62[3] |
| B−V color index | +1.69/+1.41[3] |
| Variable type | LB?[2] |
| Astrometry | |
| δ1 Aps | |
| Radial velocity (Rv) | −12.0[5] km/s |
| Proper motion (μ) | RA: −9.122±0.390[6] mas/yr Dec.: −36.968±0.505[6] mas/yr |
| Parallax (π) | 5.1748 ± 0.2734 mas[6] |
| Distance | 630 ± 30 ly (190 ± 10 pc) |
| δ2 Aps | |
| Radial velocity (Rv) | −10.2[7] km/s |
| Proper motion (μ) | RA: −1.321±0.229[6] mas/yr Dec.: −31.507±0.259[6] mas/yr |
| Parallax (π) | 5.9845 ± 0.1353 mas[6] |
| Distance | 550 ± 10 ly (167 ± 4 pc) |
| Other designations | |
| δ1 Aps: HD 145366, HIP 80047, SAO 257380.[8] | |
| δ2 Aps: HD 145388, HIP 80057, SAO 257381.[9] | |
| Database references | |
| SIMBAD | δ1 Aps |
| δ2 Aps | |
Delta Apodis (δ Aps, δ Apodis) is the Bayer designation for a double star in the southern constellation of Apus.
The brighter star, δ1 Apodis, is an M-type red giant and has an apparent magnitude that varies from magnitude +4.66 to +4.87.[11] It is classified as a semiregular variable with pulsations of multiple periods of 68.0, 94.9 and 101.7 days.[12] At an angular separation of 102.9 arcseconds is δ2 Apodis, an orange K-type giant with an apparent magnitude of +5.27.
Hipparcos data report the distance to δ1 Apodis to be approximately 760 light years, while δ2 Apodis is found to be around 610 light years from Earth. They may form a common proper motion pair.
Naming[edit]
In Chinese caused by adaptation of the European southern hemisphere constellations into the Chinese system, 異雀 (Yì Què), meaning Exotic Bird, refers to an asterism consisting of δ1 Apodis, ζ Apodis, ι Apodis, β Apodis, γ Apodis, δ Octantis, η Apodis, α Apodis and ε Apodis. Consequently, δ1 Apodis itself is known as 異雀六 (Yì Què liù, English: the Sixth Star of Exotic Bird.)[13]
References[edit]
- ^ a b c d 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, S2CID 18759600.
- ^ a b 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. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
- ^ a b c 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.
- ^ Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 1, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
- ^ Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode:1999VeARI..35....1W.
- ^ a b c d e f 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.
- ^ 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 "del01 Aps -- Pulsating variable Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-08.
- ^ a b "HR 6021 -- Star in double system", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-08.
- ^ "/ftp/cats/more/HIP/cdroms/cats". Centre de Données astronomiques de Strasbourg. Strasbourg astronomical Data Center. Retrieved 15 October 2022.
- ^ Watson, Christopher (25 August 2009). "Delta1 Apodis". The International Variable Star Index. American Association of Variable Star Observers. Retrieved 30 March 2016.
- ^ Tabur, V.; et al. (December 2009), "Long-term photometry and periods for 261 nearby pulsating M giants", Monthly Notices of the Royal Astronomical Society, 400 (4): 1945–1961, arXiv:0908.3228, Bibcode:2009MNRAS.400.1945T, doi:10.1111/j.1365-2966.2009.15588.x, S2CID 15358380.
- ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 29 日
