A feast of Asteroids!

[lukebl]

I had a great session this weekend studying my favourite celestial objects: asteroids. It was sooooo nice to get a clear night at last.

Using Astrometrica, I measure the location and magnitude of selected objects and submit them to the Minor Planet Center. It seems to be an area where amateur astronomers can still make a useful contribution to the scientific community.

These were all captured with an Atik 428ex cam and my 200mm f/5 Newtonian, tracked and stacked on the asteroid using Astrometrica. It really is amazing how quickly these little blighters move. I make no apologies for the rough-and-ready quality of the images. The measurements are the thing! The field of view of each image is about 29 x 22 arcmins.

First up is a relative biggie, 24 Themis, discovered back in 1853. About 200km across and currently at magnitude 11.7. This is the result of 86 x 1 minute exposures:

The great thing about asteroids in the main belt is that there are usually others in the same field of view, and you can make astrometric measurements of them too without having to make any more captures. Here are a some of them, also all 86 x 1 minute exposures tracked and stacked with Astrometrica.

Asteroid 46965, discovered in 1998, magnitude 17.1, about 1.25 AU distant and with an orbital period of 3.79 years:

Asteroid 72421, discovered in 2001, magnitude 16.8, about 0.84 AU distant and with an orbital period of 3.54 years

I noticed that nearby there were two asteroids very close to each other, so I had a go at capturing them. They are 4011 Bakharev and 16852 Nuredduna. Here they are. You can see their companion nearby as a streak. These captures are the result of 100 x 2 minute exposures.

Asteroid 4011 Bakharev, discovered in 1978, magnitude 16.5, about 1.14 AU distant and with an orbital period of 3.25 years. You can see Nuredduna as a streak just to its upper left:

Asteroid 16852 Nuredduna, discovered in 1997, magnitude 15.4, about 0.86 AU distant and with an orbital period of 3.4 years. You can see Bakharev as a streak just to its lower right.

An interesting thing I noted was that there doesn't seem to be any data on Nuredduna's rotation period, so I captured several hours' worth of images to enable me to prepare a light curve, and here it is. As you can see, there is a distinct curve, with an amplitude of about 0.4 magnitudes and minima at around 21:10 and 0:30. I assume that indicates a rotation period of around 3h 20m.

FINALLY, there were several other asteroids in the field of view. here is the brightest. Asteroid 5221 Fabribudweis, discovered in 1980, magnitude 17.4, about 2.41 AU distant and with an orbital period of 5.77 years.

 

[John]

What a fascinating report and series of images Luke

It's good to know that amateurs can still make a useful contribution in this way

[furrysocks2]

Inspiring stuff, esp the light curve.

Matt.

[michaelmorris]

Love the light curve.   How did you produce it?

[lukebl]

Thanks folks. The light curve was produced with Muniwin software (free) which can prepare light curves for asteroids and variable stars from a series of images.

[Stu]

Brilliant stuff Luke. Really nice to see actual data being collected and the light curve makes that little faint dot 'real' in terms of having a rotation period and presumably being an irregular shape?

Thanks!