Albireo: a magnificent double star!

Event Date: February 12th

Time: 6:00 AM

Brief

   While I focused on the Ring [Nebula] in yesterday's entry, let's take a look not far from it, to review unarguably the most popular double star seen in our sky: Albireo!  I featured it sometime while it was an evening sight, and emphasized its main characteristic: two distinguishable colors that can even be seen under low magnifications.  A medium-dark blue, and goldish-shade of yellow.  Taking a look below, we have the zoom-out and zoom-in of about 1/4º.  The software does a decent job with the colors, although it they may appear darker or lighter shades when viewed through optical aid.

   Besides our featured double, I labeled all three summer triangle stars, as well as the Ring.  Do you notice why?  See the detailed section if not, or if you want to find out if you are correct!

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

   In regards my labeling the Ring, take a look at where Altair and Vega are in relation to it: a straight line connecting both stars not only has the Ring right in path's way, yet Albireo is also not too far from it.  Therefore, besides using the parallelogram-shape that four stars near Vega make, creating the bulk of [parent constellation] Lyra the harp, this is another way to find the Ring easily.  

   Getting back to Albireo's info, the two companions are about 7 light years apart from each other, and can be split with powerful binoculars.  When viewing through a telescope with a small focal-length eyepiece, the stars are 35 arc-seconds apart; about the [angular] size of Saturn when at its mean distance from Earth.

   At 386 light years away, magnitude 3.1 yellow giant is close enough to see easily with the eye under clear skies.  On the contrary, the 5.1 blue dwarf can only be seen with the eye under very dark skies.  Even so, the stars are too close to split with the eye alone, even color-wise.  One more interesting thing is that the yellow star is a double itself; the companion is too close to see with many Earth-based telescopes.

   Enjoy Albireo as it gets higher in the sky.  A few months from now, we will beable to see Albireo for most of the night, and the entire night during the summer with the other stars that make up the triangle.