Delta Apodis

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Delta Apodis
Diagram showing star positions and boundaries of the Apus constellation and its surroundings
Cercle rouge 100%.svg

Location of δ Apodis (circled)
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) +4.76[2]
δ2 Aps
Right ascension 16h 20m 26.85843s[1]
Declination –78° 40′ 02.9901″[1]
Apparent magnitude (V) +5.27[2]
Characteristics
Spectral type M5 IIIb + K3 III[3]
U−B color index +1.68/+1.62[2]
B−V color index +1.69/+1.41[2]
Variable type irregular variable
Astrometry
δ1 Aps
Radial velocity (Rv) –12.0[4] km/s
Proper motion (μ) RA: –10.23[1] mas/yr
Dec.: –37.43[1] mas/yr
Parallax (π) 4.28 ± 0.16[1] mas
Distance 760 ± 30 ly
(234 ± 9 pc)
δ2 Aps
Radial velocity (Rv) –10.2[5] km/s
Proper motion (μ) RA: –1.75[1] mas/yr
Dec.: –31.58[1] mas/yr
Parallax (π) 5.32 ± 0.22[1] mas
Distance 610 ± 30 ly
(188 ± 8 pc)
Other designations
CP-78 1092, FK5 1424, HR 6020.[6][7]
δ1 Aps: HD 145366, HIP 80047, SAO 257380.[6]
δ2 Aps: HD 145388, HIP 80057, SAO 257381.[7]

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 a M-type red giant has an apparent magnitude that varies from magnitude +4.66 to +4.87.,[8] It is classified as a semiregular variable with pulsations of multiple periods of 68.0, 94.9 and 101.7 days.[9] 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.)[10]

References[edit]

  1. ^ a b c d e f g h i j van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ 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), Bibcode:1966CoLPL...4...99J. 
  3. ^ Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, 1, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H. 
  4. ^ Wielen, R.; et al. (1999), Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions (35), Astronomisches Rechen-Institut Heidelberg, Bibcode:1999VeARI..35....1W. 
  5. ^ Wilson, Ralph Elmer (1953), General Catalogue of Stellar Radial Velocities, Washington: Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W. 
  6. ^ a b "del01 Aps -- Pulsating variable Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-08. 
  7. ^ a b "HR 6021 -- Star in double system", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-07-08. 
  8. ^ Watson, Christopher (25 August 2009). "Delta1 Apodis". The International Variable Star Index. American Association of Variable Star Observers. Retrieved 30 March 2016. 
  9. ^ 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:0908.3228Freely accessible, Bibcode:2009MNRAS.400.1945T, doi:10.1111/j.1365-2966.2009.15588.x. 
  10. ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 29 日

External links[edit]