Regulas, Algieba and 54 Leonis.
Posted 07 April 2009 - 11:37 PM
Regulus was a fun observation. Regulus A is very evident as a bright blue star in the center of the sketch. I saw what I thought was its companion which is smaller to the SW of Regulus A. However, after studying this I found that the companion of Regulus A is most likely a white dwarf that explains the rapid rotation of this star and its shape. Regulus is actually a quadruple star.Regulus B is a smaller dwarf star of spectral type K2 which would make it significantly dimmer than A. The final companion, Regulus C, is a small red star and the faintest of the three stars which have been directly observed. Regulus A is itself a spectroscopic binary: the secondary star has not yet been directly observed as it is much fainter than the primary. The BC pair lies at an angular distance of 177 arc-seconds from Regulus A, making them visible in amateur telescopes.
More information can be found here.
Algieba is in Leo also and is made up of two stars that are giants, the larger being a K star and the companion being a G star. "The giant K star has a surface temperature of 4,470 K, a luminosity 180 times that of Earth's Sun, and a diameter 23 times that of the Sun. he giant G star has a temperature of 4,980 K, a luminosity of 50 times that of the Sun, and a diameter 10 times that of the Sun. With angular separation of just over 4", the two stars are at least 170 AU apart (four times the distance between Pluto and the Sun), and have an orbital period of over 500 years. Because the orbital period is so long, only a fraction of the full path has been observed since discovery."
I found it interesting in the scholarly online base of knowledge Wikipedia (I did quote it above) the argument is that these are two giant stars whose cores are fusing helium
in their cores, or they are young stars whose helium core haven't fired up yet.
Leonis 54 shows a bright primary that is mainly white, while the companion is a very nice blue.
I need to figure out how to get my compass points down as I'm not happy with them or with a few things.
Posted 08 April 2009 - 12:58 PM
I'm looking forward to seeing ongoing additions to your double/multiple star collection!
Posted 08 April 2009 - 01:27 PM
All very eyepiece realistic. Nicely done and thanks for posting all.
Posted 08 April 2009 - 02:06 PM
Thanks for your comments. I really enjoyed viewing them and will continue to do so. I had three okay viewing days, and now four or five rainy ones coming. That's spring in Utah. I would like to see the double by the Tao Cluster h 3945 (I believe). I read about that today in the doubles thread and then looked up info on the net. It seems that some call it the winter Alberio. Next week I hope when the weather has cleared and my painting/packing is done, by Sunday I hope (I hate moving but the new home would be ideal for a suburban area for an observatory . . . ).
Posted 08 April 2009 - 03:21 PM
I think that you do a great job with these sketches, as with the previous posts. I enjoy each and every one of them.
Posted 09 April 2009 - 03:59 AM
Excellent observations of Regulus, Algieba, and 54 Leonis. You have captured all of these interesting double stars very nicely. The spikes of the stars produced using Gimp is very nice as well. Thank you for sharing them with us all.