Apus

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For the high school college credit course, see Advanced Placement United States History. For other uses, see Apus (disambiguation).
Apus
Constellation
Apus
Abbreviation Aps
Genitive Apodis
Pronunciation /ˈpəs/, genitive /ˈæpəds/
Symbolism The Bird-of-Paradise[1]
Right ascension 13h 51m 07.5441s–18h 27m 27.8395s[2]
Declination −67.4800797°–−83.1200714°[2]
Family Bayer
Area 206 sq. deg. (67th)
Main stars 4
Bayer/Flamsteed
stars
12
Stars with planets 2
Stars brighter than 3.00m 0
Stars within 10.00 pc (32.62 ly) 0
Brightest star α Aps (3.83m)
Nearest star HD 128400
(66.36 ly, 20.35 pc)
Messier objects None
Meteor showers None
Bordering
constellations
Triangulum Australe
Circinus
Musca
Chamaeleon
Octans
Pavo
Ara
Visible at latitudes between +5° and −90°.
Best visible at 21:00 (9 p.m.) during the month of July.

Apus is a small constellation in the southern sky, first defined in the late 16th century. Its name means "no feet" in Greek, and it represents a bird-of-paradise, which was once wrongly believed to lack feet. Its genitive is "Apodis". The orange giant Alpha Apodis is the brightest star in the constellation. Two star systems have been found to have planets.

History[edit]

Apus was one of twelve constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman who had sailed on the first Dutch trading expedition, known as the Eerste Schipvaart, to the East Indies. It first appeared on a 35-cm (14 in) diameter celestial globe published in 1598 in Amsterdam by Plancius with Jodocus Hondius.[3] De Houtman included it in his southern star catalogue in 1603 under the Dutch name De Paradijs Voghel, "The Bird of Paradise",[4] and Plancius called the constellation Paradysvogel Apis Indica; the first word is Dutch for "bird of paradise". Apis (Latin for "bee") is presumably a typographical error for avis ("bird").[1] Bayer called it Apis Indica while Johannes Kepler and his son in law Jacob Baertsch called it Apus or Avis Indica.[5] The name Apus is derived from the Greek apous, meaning "without feet". This referred to the Western misconception that the bird-of-paradise had no feet, which arose because the only specimens available in the West had their feet and wings removed. Such specimens began to arrive in Europe in 1522, when the survivors of Ferdinand Magellan's expedition brought them home.[1]

After its introduction on Plancius's globe, the constellation's first known appearance in a celestial atlas was in German cartographer Johann Bayer's Uranometria of 1603,[3] where it was called "Apis Indica".[1]

Richard Allen reports Semler's assertion that de Houtman, who observed the southern constellations from the island of Sumatra, took his ideas for the formation of Apus (as well as Phoenix and Indus) from the Chinese, who knew the stars of Apus as the "Little Wonder Bird",[6] and that Semler's assertion was disputed by Ideler (though Ideler acknowledged the Chinese constellations).

Characteristics[edit]

Covering 206.3 square degrees and hence 0.500% of the sky, Apus ranks 67th of the 88 modern constellations by area.[7] Its position in the Southern Celestial Hemisphere means that the whole constellation is visible to observers south of 7°N.[7][a] It is bordered by Ara, Triangulum Australe and Circinus to the north, Musca and Chamaeleon to the west, Octans to the south, and Pavo to the east. The three-letter abbreviation for the constellation, as adopted by the International Astronomical Union in 1922, is 'Aps'.[8] The official constellation boundaries, as set by Eugène Delporte in 1930, are defined by a polygon of six segments (illustrated in infobox). In the equatorial coordinate system, the right ascension coordinates of these borders lie between 13h 49.5m and 18h 27.3m, while the declination coordinates are between -67.48° and -83.12°.[2]

Notable features[edit]

The constellation Apus as it can be seen by the naked eye.

Stars[edit]

Lacaille gave twelve stars Bayer designations, labelling them Alpha through to Kappa, including two stars next to each other as Delta and another two stars near each other as Kappa.[5] Within the constellation's borders, there are 39 stars brighter than or equal to apparent magnitude 6.5.[b][7] Beta, Gamma and Delta Apodis form a narrow triangle, with Alpha Apodis lying to the east.[10]

Alpha Apodis is an orange giant of spectral type K3III 447 ± 8 light years away from Earth,[11] with a magnitude of 3.8.[12][13] It spent much of its life as a blue-white (B-type) main sequence star before expanding, cooling and brightening as it used up its core hydrogen,[14] now shining with a luminosity approximately 928 times that of the Sun, with a surface temperature of 4312 K.[15] Beta Apodis is an orange giant 157 ± 2 light years away,[11] with a magnitude of 4.2.[12] It is around 1.84 times as massive as the Sun, with a surface temperature of 4677 K.[16] Gamma Apodis is an yellow giant of spectral type G8III located 156 ± 1 light-years away,[11] with a magnitude of 3.87. It is approximately 63 times as luminous the Sun, with a surface temperature of 5279 K.[15] Delta Apodis is a double star, the two components of which are 103 arcseconds apart and visible through binoculars.[17] Delta1 is a red giant star of spectral type M4III located 760 ± 30 light years away.[11] It is a semiregular variable that varies from magnitude +4.66 to +4.87,[18] with pulsations of multiple periods of 68.0, 94.9 and 101.7 days.[19] Delta2 is an orange giant star[13] located 610 ± 30 light years away,[11] with a magnitude of 5.3. The separate components can be resolved with binoculars, a telescope, or the naked eye.[12]

Zeta Apodis is a star that has swollen and cooled to become an orange giant of spectral type K1III, with a surface temperature of 4649 K and a luminosity 133 times that of the Sun.[15] It is 297 ± 8 light-years distant.[11]

Eta Apodis is a white main sequence star located 138 ± 1 light-years distant.[11] Of apparent magnitude 4.89, it is in reality 1.77 times as massive, 15.5 times as luminous as the Sun and has 2.13 times its radius. Aged 250 ± 200 milion years old, this star is emitting an excess of 24 μm infrared radiation, which may be caused by a debris disk of dust orbiting at a distance of more than 31 astronomical units from it.[20]

Theta Apodis is a cool red giant of spectral type M7 III located 370 ± 20 light years distant.[11] It shines with a luminosity approximately 3879 times that of the Sun and has a surface temperature of 3151 K.[15] A semiregular variable, it varies by 0.56 magnitudes with a period of 119 days[21]—or approximately 4 months,[12] It is losing mass at the rate of 1.1 × 10−7 times the mass of the Sun per year through its stellar wind. Dusty material ejected from this star is interacting with the surrounding interstellar medium, forming a bow shock as the star moves through the galaxy.[22]

Iota Apodis is a binary star system around 1300 light-years distant,[11] that is composed of two blue-white main sequence stars that orbit each other every 51.441 years.[23] Of spectral types B9V and B9.5 V, they are each around three times as massive as the Sun.[24]

NO Apodis is a red giant of spectral type M3III that varies between magnitudes 5.71 and 5.95.[25] Located around 883 light-years distant, it shines with a luminosity approximately 2059 times that of the Sun and has a surface temperature of 3568 K.[15] S Apodis is a rare R Coronae Borealis variable, an extremely hydrogen-deficient supergiant thought to have arisen as the result of the merger of two white dwarfs; fewer than 100 have been discovered as of 2012. It has a baseline magnitude of 9.7.[26]

Two star systems have had exoplanets discovered by doppler spectroscopy, and the substellar companion of a third star system—the sunlike star HD 131664—has turned out to be a brown dwarf with a predicted mass of the companion to 23 times that of Jupiter (minimum of 18 and maximum of 49 Jovian masses).[27] HD 134606 is a yellow sunlike star of spectral type G6IV that has begun expanding and cooling off the main sequence.[28] Three planets orbit it with periods of 12, 59.5 and 459 days, successively larger as they are further away from the star.[29] HD 137388 is another star—of spectral type K2IV—that is cooler than the Sun and has begun cooling off the main sequence.[28] Around 47% as luminous and 88% as massive as the Sun, with 85% of its diameter, it is thought to be around 7.4 ± 3.9 billion years old.[30] It has a planet that is 79 times as massive as the Earth and orbits its sun every 330 days at an average distance of 0.89 AU. [31]

Deep-sky objects[edit]

The most prominent deep-sky objects in Apus include the globular clusters NGC 6101 and IC 4499 as well as the spiral galaxy IC 4633.

  • NGC 6101 is a 14th magnitude globular cluster, located seven degrees north of Gamma Apodis.[13]
  • IC 4499 is a loose globular cluster in the medium-far galactic halo.[33] Its apparent magnitude is 10.6,[34] and it is unique because it is younger than most other globular clusters in the same region as determined by its metallicity.[33]
  • IC 4633 is a very faint spiral galaxy [13] surrounded by a vast amount of Milky Way line-of-sight Integrated Flux Nebulae.

Equivalents[edit]

When the Ming Dynasty Chinese astronomer Xu Guangqi adapted the European southern hemisphere constellations to the Chinese system in The Southern Asterisms, he combined Apus with some of the stars in Octans to form the "Exotic Bird" (異雀, Yìquè).[35]

Notes[edit]

  1. ^ While parts of the constellation technically rise above the horizon to observers between the 7°N and 22°N, stars within a few degrees of the horizon are to all intents and purposes unobservable.[7]
  2. ^ Objects of magnitude 6.5 are among the faintest visible to the unaided eye in suburban-rural transition night skies.[9]

References[edit]

Citations
  1. ^ a b c d Ridpath, Ian. "Apus". Star Tales. Retrieved 10 April 2012. 
  2. ^ a b c "Apus, constellation boundary". The Constellations (International Astronomical Union). Retrieved 14 February 2014. 
  3. ^ a b Ridpath, Ian. "Johann Bayer's Southern Star Chart". Star Tales. self-published. Retrieved 30 May 2016. 
  4. ^ Ridpath, Ian. "Frederick de Houtman's Catalogue". Star Tales. self-published. Retrieved 30 May 2016. 
  5. ^ a b Wagman, Morton (2003). Lost Stars: Lost, Missing and Troublesome Stars from the Catalogues of Johannes Bayer, Nicholas Louis de Lacaille, John Flamsteed, and Sundry Others. Blacksburg, VA: The McDonald & Woodward Publishing Company. pp. 30–32. ISBN 978-0-939923-78-6. 
  6. ^ Richard H. Allen (1899) Star Names: Their Lore and Meaning, p. 45 <http://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Apus*.html>
  7. ^ a b c d Ridpath, Ian. "Constellations: Andromeda–Indus". Star Tales. self-published. Retrieved 26 August 2015. 
  8. ^ Russell, Henry Norris (1922). "The New International Symbols for the Constellations". Popular Astronomy 30: 469. Bibcode:1922PA.....30..469R. 
  9. ^ Bortle, John E. (February 2001). "The Bortle Dark-Sky Scale". Sky & Telescope. Retrieved 26 August 2015. 
  10. ^ Thompson, Mark (2013). A Down to Earth Guide to the Cosmos. Random House. ISBN 978-1-4481-2691-0. 
  11. ^ a b c d e f g h i van Leeuwen, F. (2007). "Validation of the New Hipparcos Reduction". Astronomy and Astrophysics 474 (2): 653–64. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. 
  12. ^ a b c d Ridpath 2001, pp. 76-77.
  13. ^ a b c d Plotner, Tammy (13 October 2008). "Apus". Universe Today. Retrieved 22 April 2012. 
  14. ^ Kaler, James B. (6 April 2007). "Alpha Aps". Stars. University of Illinois. Retrieved 30 March 2016. 
  15. ^ a b c d e McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012). "Fundamental Parameters and Infrared Excesses of Hipparcos Stars". Monthly Notices of the Royal Astronomical Society 427 (1): 343–57. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x. 
  16. ^ Liu, Y. J.; Zhao, G.; Shi, J. R.; Pietrzyński, G.; Gieren, W. (2007). "The abundances of nearby red clump giants". Monthly Notices of the Royal Astronomical Society 382 (2): 553–66. Bibcode:2007MNRAS.382..553L. doi:10.1111/j.1365-2966.2007.11852.x. 
  17. ^ Privett, Grant; Jones, Kevin (2013). The Constellation Observing Atlas. New York, New York: Springer Science & Business Media. p. 13. ISBN 978-1-4614-7648-1. 
  18. ^ Watson, Christopher (25 August 2009). "Delta1 Apodis". The International Variable Star Index. American Association of Variable Star Observers. Retrieved 30 March 2016. 
  19. ^ Tabur, V.; Bedding, T.R.; Kiss, L.L.; Moon, T.T.; Szeidl, B.; Kjeldsen, H. (2009). "Long-term photometry and periods for 261 nearby pulsating M giants". Monthly Notices of the Royal Astronomical Society 400 (4): 1945–61. arXiv:0908.3228. Bibcode:2009MNRAS.400.1945T. doi:10.1111/j.1365-2966.2009.15588.x. 
  20. ^ Plavchan, Peter; Werner, M.W.; Chen, C.H.; Stapelfeldt, K.R.; Su, K.Y.L.; Stauffer, J.R.; Song, I. (2009). "New Debris Disks Around Young, Low-Mass Stars Discovered with the Spitzer Space Telescope". The Astrophysical Journal 698 (2): 1068–94. arXiv:0904.0819. Bibcode:2009ApJ...698.1068P. doi:10.1088/0004-637X/698/2/1068. 
  21. ^ Yeşilyaprak, C.; Aslan, Z. (2004). "Period-luminosity relation for M-type semiregular variables from Hipparcos parallaxes". Monthly Notices of the Royal Astronomical Society 355 (2): 601–07. Bibcode:2004MNRAS.355..601Y. doi:10.1111/j.1365-2966.2004.08344.x. 
  22. ^ Cox, N.L.J.; Kerschbaum, F.; van Marle, A.-J.; Decin, L.; Ladjal, D.; Mayer, A.; Groenewegen, M. A. T.; van Eck, S.; Royer, P.; Ottensamer, R.; Ueta, T.; Jorissen, A.; Mecina, M.; Meliani, Z.; Luntzer, A.; Blommaert, J.A.D.L.; Posch, Th.; Vandenbussche, B.; Waelkens, C. (2012). "A far-infrared survey of bow shocks and detached shells around AGB stars and red supergiants". Astronomy & Astrophysics 537: A35. arXiv:1110.5486. Bibcode:2012A&A...537A..35C. doi:10.1051/0004-6361/201117910.  See table 1, IRAS 14003-7633.
  23. ^ Olević, D.; Cvetković, Z. (2004). "Orbits of 10 interferometric binary systems calculated by using the improved Koval'skij method". Astronomy and Astrophysics 415: 259–64. Bibcode:2004A&A...415..259O. doi:10.1051/0004-6361:20034069. 
  24. ^ Docobo, J.A.; Andrade, M. (2013). "Dynamical and physical properties of 22 binaries discovered by W. S. Finsen". Monthly Notices of the Royal Astronomical Society 428 (1): 321–39. Bibcode:2013MNRAS.428..321D. doi:10.1093/mnras/sts045. 
  25. ^ Watson, Christopher (25 August 2009). "NO Apodis". The International Variable Star Index. American Association of Variable Star Observers. Retrieved 31 March 2015. 
  26. ^ Tisserand; Clayton; Welch; Pilecki; Wyrzykowski; Kilkenny (2012). "The Ongoing Pursuit of R Coronae Borealis Stars: ASAS-3 Survey Strikes Again". Astronomy & Astrophysics 551: 22. arXiv:1211.2475. Bibcode:2013A&A...551A..77T. doi:10.1051/0004-6361/201220713. A77. 
  27. ^ Reffert, S.; Quirrenbach, A. (2011). "Mass constraints on substellar companion candidates from the re-reduced Hipparcos intermediate astrometric data: nine confirmed planets and two confirmed brown dwarfs". Astronomy & Astrophysics 527. id.A140. arXiv:1101.2227. Bibcode:2011A&A...527A.140R. doi:10.1051/0004-6361/201015861. 
  28. ^ a b Gray, R.O.; Corbally, C.J.; Garrison, R.F.; McFadden, M.T.; Bubar, E.J.; McGahee, C.E.; O'Donoghue, A.A.; Knox, E.R. (July 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. 
  29. ^ Schlaufman, Kevin C. (2014). "Tests of in situ Formation Scenarios for Compact Multiplanet Systems". The Astrophysical Journal 790 (2): 11. Bibcode:2014ApJ...790...91S. doi:10.1088/0004-637X/790/2/91. 91. 
  30. ^ Bonfanti, A.; Ortolani, S.; Piotto, G.; Nascimbeni, V. (2015). "Revising the ages of planet-hosting stars". Astronomy & Astrophysics 575 (A18): 17. arXiv:1411.4302. Bibcode:2015A&A...575A..18B. doi:10.1051/0004-6361/201424951. 
  31. ^ Dumusque, X.; Lovis, C.; Ségransan, D.; Mayor, M.; Udry, S.; Benz, W.; Bouchy, F.; Lo Curto, G.; Mordasini, C.; Pepe, F.; Queloz, D.; Santos, N. C.; Naef, D. "The HARPS Search for Southern Extra-solar Planets. XXX. Planetary Systems around Stars with Solar-like Magnetic Cycles and Short-term Activity Variation". Astronomy & Astrophysics 535: A55–A66. arXiv:1107.1748. Bibcode:2011A&A...535A..55D. doi:10.1051/0004-6361/201117148. 
  32. ^ "IC 4499: A globular cluster’s age revisited". ESA/Hubble Picture of the Week. Retrieved 5 August 2014. 
  33. ^ a b Ferraro, I.; Ferraro, F.R.; Pecci, F. Fusi; Corsi, C.E.; Buonanno, R. (August 1995). "Young globular clusters in the Milky Way: IC 4499". Monthly Notices of the Royal Astronomical Society (SAO/NASA ADS Astronomy Abstract Service) 275 (4): 1057–1076. Bibcode:1995MNRAS.275.1057F. doi:10.1093/mnras/275.4.1057. Retrieved 22 April 2012. 
  34. ^ Frommert, Hartmut. "IC 4499". Students for the Exploration and Development of Space. Retrieved 22 April 2012. 
  35. ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 29 日
References
  • Ridpath, Ian (2001), Stars and Planets Guide, Princeton University Press, ISBN 0-691-08913-2 
  • Ridpath, Ian (2007), Stars and Planets Guide, Wil Tirion (4th ed.), Princeton University Press, ISBN 978-0-691-13556-4 
  • Staal, Julius D.W. (1988), The New Patterns in the Sky: Myths and Legends of the Stars, The McDonald and Woodward Publishing Company, ISBN 0-939923-04-1 

External links[edit]

Coordinates: Sky map 16h 00m 00s, −75° 00′ 00″