The Webb Deep-Sky Society
Double Star of the Month - February 2009
|
In this series of short articles, a double star in both the northern and southern hemispheres will be highlighted for observation with small telescopes, with new objects being selected for each month. STF1338
(09 20 59.4 +38 11 17.9) is a beautiful binary about 1.5 degrees north of the
4th magnitude star 38 Lyncis which is also a pretty pair. Its almost equal
components are given as mags 6.72 and 7.08 in the WDS which also notes a third
faint star (mag 11.4) some 144" away in PA 166 degs. Hartung finds the colours
both bright yellow whilst Smyth and Chambers in the Cycle of Celestial Objects
second edition of 1881 give both stars to be white. The WDS perhaps favours the
latter colours listing the spectral types as F2V and F4V. Orbital motion is slow
and from the discovery position of 121 degrees, 1".76 the pair has advanced to
303 degrees, 1".01 in 2009 according to the 303 year period given in the USNO
6th Orbit Catalogue. This pair is 42 parsecs distant according to Hipparcos and
is an easy object in a small telescope at all times. It reached a maximum
distance of 1".65 in 1865 and closest approach will be about 0".96 in 2044. |
Bob Argyle