Is this extra 'star' an Asteroid?

[Stub Mandrel]

This is really embarrassing, because I suspect almost everyone who has been observing for a few months 'discovers' a new star... but I feel bound to ask.

I took a series of pictures of the Ring nebula, and have loaded the star catalogues into Stellarium and have been wandering a round the picture trying to get a handle on what magnitude of stars I have been able to pick up (about 15 as it happens).

What has caught my eye is a very obvious binary to the east of the nebula that isn't shown as such on stellarium. The main star is mag 11.45 and the apparent 'companion' is by comparison about mag 13-14.

On the four out of eight images I took where the stars came out round, it is clear as a separate dot, so it isn't an artefact and it's too big to be a hot pixel. It actually looks less separated in the stacked version than it does in the raw images. It isn't moving fast enough to be a satellite, even a geostationary one would have streaked - four 30S subs taken over about 8  minutes.

I can't figure out how to get asteroids into stellarium to check, but is it possible that this is one?

[Uranium235]

Looks like a double star to me, these are quite common - i can sometimes mistake them for coma at the edge of field. Sometimes if you zoom right into the star on stellarium, the double then becomes apparent (unless its not in your current catalogue).

To check if its an asteroid you would need a series of images, then flick between them to see whether its moving.

[wxsatuser]

The star nearer your arrow is UCAC4-616-066143 at about Mag 11

The other star is double star  WDS ES 2234, two components one at Mag 13 the other 12.5.

[Stub Mandrel]

Does this mean Stellarium shows a lot of binaries as single stars?

[ronin]

Probably depends on the seperation and the "importance" of the double.

Also not sure which set of catalogues Stellarium obtains it's data from.

One strange aspect is that Albireo is a well know coloured double star, but how many have seen a reference to the 2 stars that make up the double, similar for Almaak.

There are most likely too many "insignificant" double stars for all to be identified, or have accurate known data, so they default to a single. Cannot recall but I believe that the majority of stars are doubles, we are orbiting an odd star in that it is a single.

Maybe's after Gaia delivers data many will get updated, but that will be a good number of years. Also Gaia seems to be very quite, not heard any reports of new astounding data from it, not actually heard any reports of data from it, never mind new and astounding.

[Stub Mandrel]

Gaia - new one on me, but still live: http://sci.esa.int/gaia/56123-counting-stars-with-gaia/

[wxsatuser]

Does this mean Stellarium shows a lot of binaries as single stars?

I use Cartes du Ciel and have Washington Double Stars turned on.

The seperation of this double is 6.3arcsecs

[Stub Mandrel]

Marathon star database download now in progress...