Starship Asterisk*

Stunning image. Looking closer I see an odd shape in the fine blue haze (I assume that it is part of the neb) it looks rathe like a couple of brackets thus ( )) it seems to be situated at the logical position of the pulsar, so I am wondering if it is a function of the star itself or just an illusion...

Starnut, thanks for the path to the Galex site I never spotted that. Double star and Binary though are not quite the same thing, many listed doubles are visual only (Albireo in Cygnus for example) and have no physical association, whereas a binary system is a pair (or more) of stars in gravitational...

Given that the tail started forming at it's current start position (hypothetical) I calculate that the star has been leaving this trail for around 30,000 yrs based on it's current speed.

Anyone confirm or correct this?

Mira is a known double star and is also part of a Binary system

I thought at first that they must all orbit the common centre of gravity, but that would not account for the stars near the axis of rotation. Cosidering that (I seem to remember reading somewhere) the average distance between the stars in a GC is about 1 LY, I wonder how much gravitational influence...

http://watercolor-landscapes-online.co.uk/Downloads/APOD-Abell39.jpg This annotated version should help a little, the yellow borderline lies just outside the nebula limit, I have brightened the nebula a little, but this then does not give an accurate image of it's true brightness in comparison to t...

Not sure as to why it is spherical, but a great many of these faint PN's exhibit a similar structure, they are faint because they are very large and spread out, hence it's fairly logical to assume they are at a very advanced stage (old!) maybe by this time in the PN's existence the expansion has eve...

I downloaded the 121530main_its_approach_x4.mov which shows a sequence from nothing in sight to seconds before impact, it's very impressive of course, but it would also be useful to know the time between frames so that a more accurate idea of the approach speed can be envisaged.