Shirt a Phobia

Sample Page

Epsilon Chamaeleontis is a triple star located in the southern circumpolar constellation Chamaeleon. Its name is a Bayer designation that is Latinized from ε Chamaeleontis, and abbreviated Epsilon Cha or ε Cha. The primary and secondary have apparent magnitudes of 5.33 and 6.02, making them visible to the naked eye. Hipparcos parallax measurements place the system at a distance of 360 light years[7] and is currently receding with a heliocentric radial velocity of 13 km/s.[6]

Properties

The binary nature of this system was first observed during February 1836 when Sir John Herschel found it as the close double star, HJ 4486AB.[12] In 2016, it was discovered that Epsilon Chamaeleontis A it a binary system itself, with components designated Aa and Ab, thus making the system triple.[13] The inner (Aa-Ab) system has an orbital period of 6.43 years and a high eccentricity of 0.643, while the outer (A-B) system has an orbital period of 751 years and a circular orbit.[8]

The system is a member of the of Scorpius-Centaurus Association or the smaller portion known as the Lower Centaurus Crux subgroup. The system forms the nucleus of the very young Epsilon Chamaeleontis stellar group, which comprises at least 36 stars.[9] The nebulosity and star formation occurring in this region is currently a very important line of study in the southern hemisphere, whose proximity to the Sun is yielding new astrophysical information. Several papers have been published in the last few years on Lower Centaurus Crux subgroup of stars in the far southern constellations of Musca, Chamaeleon and Octans holding the south celestial pole.[14]

References

  1. ^ 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. XHIP record for this object at VizieR.
  2. ^ a b c d e f g Fabricius, C.; Høg, E.; Makarov, V. V.; Mason, B. D.; Wycoff, G. L.; Urban, S. E. (March 2002). “The Tycho double star catalogue”. Astronomy & Astrophysics. 384 (1): 180–189. Bibcode:2002A&A…384..180F. doi:10.1051/0004-6361:20011822. eISSN 1432-0746. ISSN 0004-6361.
  3. ^ Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Volume I. Declinations −90° to −53°. Bibcode:1975mcts.book…..H.
  4. ^ a b Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). “UBVRIJKL Photometry of the Bright Stars”. Communications of the Lunar and Planetary Laboratory. 4: 99–110. Bibcode:1966CoLPL…4…99J.
  5. ^ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (December 2001). “The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog”. The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ….122.3466M. doi:10.1086/323920. ISSN 0004-6256.
  6. ^ a b Kharchenko, N.V.; Scholz, R.-D.; Piskunov, A.E.; Röser, S.; Schilbach, E. (November 2007). “Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ~55000 stars and mean radial velocities of 516 Galactic open clusters and associations”. Astronomische Nachrichten. 328 (9): 889–896. arXiv:0705.0878. Bibcode:2007AN….328..889K. doi:10.1002/asna.200710776. eISSN 1521-3994. ISSN 0004-6337. S2CID 119323941.
  7. ^ a b c van Leeuwen, Floor (13 August 2007). “Validation of the new Hipparcos reduction”. Astronomy & Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A…474..653V. doi:10.1051/0004-6361:20078357. eISSN 1432-0746. ISSN 0004-6361. Hipparcos record for this source at VizieR.
  8. ^ a b c d e f Tokovinin, Andrei (April 2023). “Dynamics of Four Triple Systems”. The Astronomical Journal. 165 (4): 165. arXiv:2304.01863. Bibcode:2023AJ….165..165T. doi:10.3847/1538-3881/acbf32. ISSN 0004-6256.
  9. ^ a b c d Dickson-Vandervelde, D. Annie; Wilson, Emily C.; Kastner, Joel H. (28 January 2021). “Gaia-based Isochronal, Kinematic, and Spatial Analysis of the ϵ Cha Association”. The Astronomical Journal. 161 (2): 87. arXiv:2011.06621. Bibcode:2021AJ….161…87D. doi:10.3847/1538-3881/abd0fd. eISSN 1538-3881. ISSN 0004-6256.
  10. ^ Gould, Benjamin Apthorp (1878). “Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas”. Resultados del Observatorio Nacional Argentino. 1. Bibcode:1879RNAO….1…..G.
  11. ^ “* eps Cha”. SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-12-11.
  12. ^ Herschel, J. F. W. (1836). “Sixth Catalogue of Double Stars, observed at Slough, in the years 1831 and 1832, with the 20-fet Reflector; containing the Places, Descriptions, and Measured Angles of Position of 286 of those Objects, of which 105 have not been previously described. Reduced to the Epoch 1830·0”. Memoirs of the Royal Astronomical Society. 9: 193. Bibcode:1836MmRAS…9..193H.
  13. ^ Tokovinin, Andrei; Mason, Brian D.; Hartkopf, William I.; Mendez, Rene A.; Horch, Elliott P. (2016-05-25). “SPECKLE INTERFEROMETRY AT SOAR IN 2015*”. The Astronomical Journal. 151 (6): 153. doi:10.3847/0004-6256/151/6/153. ISSN 0004-6256.
  14. ^ Jilinski, E.; Ortega, V. G.; de la Reza, R. (February 2005). “On the Origin of the Very Young Groups η and ε Chamaeleontis”. The Astrophysical Journal. 619 (2): 945–947. Bibcode:2005ApJ…619..945J. doi:10.1086/426535. eISSN 1538-4357. ISSN 0004-637X.

Further reading