Category: multiple

Wolf-Rayet in Vela

Gamma Velorum

Gamma Velorum
By Rogerio Eirado

The brilliant Gamma Velorum system is composed of at least 6 stars. The primary star of this system is actually a spectroscopic binary that has been dubbed the Spectral Gem of the Southern Skies because its exotic spectrum is dominated by bright emission lines rather than dark absorption lines. It is composed of an O9 blue giant and a massive Wolf-Rayet star that are separated by 1 AU and orbit with a period of 78.5 days. The Wolf-Rayet star probably started its life at around 40 solar masses, but has blown most of that mass away and is now probably closer to 10 solar masses. Both stars in this pair have extremely powerful winds, and as these winds collide they produce X-Ray emissions. The Wolf-Rayet star is likely in the last stages of its path toward exploding as a Supernova. It’s companion will eventually follow suit. The B component seen in Rogerio’s sketch is a B-class subgiant and the C and D components (lined up above the A and B components in the sketch) are white A-class stars. The D component itself has a much fainter and challenging 13th magnitude companion separated from it by 1.8 arc seconds (the 6th star in the system).

Rogerio sketched this beautiful multiple star using pencil on white paper. The sketch was then scanned, inverted to a positive image, and digital methods were used to enhance and add observed color to the stars. His sketch gallery can be found here: A vida, o universo e tudo o mais.

Sources: Burnham’s Celestial Handbook, Jim Kaler’s ‘Regor’, Wikipedia

Multiple Stars – Split Personalities

Multiple stars 

Due to my newly found enthusiasm for observing, measuring and, of
course, sketching Double and Multiple Star Systems, I’ve decided to
present a selection of some of the most well-known star systems of that
kind.

Clockwise starting in the upper left corner, you will find Mizar and
Alkor in Ursa major, already known since ancient times. The upper right
corner shows Albireo, the indicator of late summer / early autumn and
for many observers one of the best double stars in the sky. The lower
right corner shows Epsilon lyrae, the famous double Double, I got the
proportions wrong there, nevertheless a fascinating sight. Finally, the
lower left corner is a drawing of Alamak in Andromeda, the “Autumn
Albireo”, as many call it, shining in the colors yellow and blue-green.
These four sketches represent the most well-known double stars,
basically any observer knows, however there are many other fantastic and
rewarding Double and Multiple Star Systems out there, so when you are
planning your next observing night, maybe you are going to visit one or two.

All sketches were made with a 6″ Newtonian f/5 at varying
magnifications, the conditions were good, around 6 mag, Bortle 4-5
skies, average seeing, pencil sketches, digitally re-worked.

Don’t forget to click on the sketch, which will take you to a larger
version and a better view!

Sebastian Lehner