|
Epsilon Chamaeleontis (Epsilon Cha, ε Chamaeleontis, ε Cha), is a star located in the constellation Chamaeleon at Right Ascension and Declination −78° 13 arcmin 19 arcsec.. Epsilon Chamaeleontis is also known as the star HIP 48484, HR 4583, or HD 104174, and to the naked-eye is of visual magnitude of +4.88, Distance is 111±4 pc (362±14 light years) from the Sun, whose absolute magnitude of −0.361. Radial velocity is +13 km.s−1, whose individual Hipparcos proper motions are −40.34±0.38 mas.yr−1 in Right Ascension and −8.30±0.40 mas.yr−1in Declination. It is also double star HJ 4486AB, as discovered by Sir John Herschel during February 1836, and is a likely binary system, though no formal orbit has yet been determined. Observations through the 20th Century have been slowly reducing, whose latest separation is 0.364 arcsec in position angle 211°, as determined on date 1997.0905 using CCD speckle interferometry by E.P. Horch (1997). Epsilon Chamaeleontis A or HJ 4486A is an B9Vn dwarf star with an effective temperature of 11000 Kelvin. Apparent visual magnitude of +5.3, and has a mass of 3.3 solar masses. Epsilon Chamaeleontis B or HJ 4486B is also a dwarf star of undetermined 'A' spectral type with an effective temperature of about 9600 Kelvin, being based on the lesser apparent visual magnitude of +6.1, and is about 3.0 solar masses. Observation of the spectrum show strong nebula lines, suggesting the stars are of a young age. Both stars are members of Scorpius-Centaurus Association or the smaller portion known as the Lower Centaurus Crux subgroup. The double star forms the nucleus of the very young Epsilon Chamaeleontis stellar group which comprises about twenty stars. 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. == References == *http://www.alcyone.de/cgi-bin/search.pl?object=HR4583 *http://server3.wikisky.org/starview?object_type=1&object_id=1646 *http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HR+4231&submit=SIMBAD+search 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Epsilon Chamaeleontis」の詳細全文を読む スポンサード リンク
|