M42 - Trapezium - Your help needed!

[david scanlan]

Hi All,

As many of you know I am the current director of the SPA Variable Star Section and during my usual variable rounds I have come across information concerning the Trapezium which I think could be totally wrong

Star BM Ori in the trapezium is an eclipsing binary and many sources state its mag variation at between 7.9 - 8.9 however on a recent observation I put the star at around magnitude 12.0 and other observers observing on the same night also put it within this area

This has made me conclude that the range of this star which is commonly accepted could be totally wrong...as could the period of the binary star

I have embarked on research to gather as many observations as possible of the trapezium over a couple of years so if any of you have either imaged the trapezium within the last 24 months or done any variable star estimates on any of the stars in the tapezium can you please let me know.

The reason this may have been overlooked is that the trapezium is not commonly known to be variable stars so theres a good chance here I could make a discovery in the name of the Society for Popular Astronomy

Please let me know if you have anything to offer

Dave

[Trevor]

Dave

Are you talking about Theta 1 B. B Ori, of the 4 it’s the top (north) of the trapezium.

Trev.

[david scanlan]

Hi

Its listed in charts as B. Bottom left hand corner

Regards

Dave

[Trevor]

That’s the one Dave.

[david scanlan]

Hi

Just getting confirmation for definite on the name as I may have made a mistake :-(

There seems to be much conflicting information about the trapezium variables :-(

Dave

[david scanlan]

Panic over I was right

Theta 1 B is also known as BM Ori in the GCVS

Dave

[Graham]

Hi Dave,

I was "playing" with my new scope on 10 - 11/01/2008 at around 23:50 UTC. It's a bit out of focus - but as I say I was only playing; the photo below is cropped and compressed...I've got a few others, full size, from the same night jpg & cr2 if they're any use.

Cheers,

Graham

(click to enlarge)

[david scanlan]

Thanks

Yeah the others will be of use.

Please either post them onto here or send them via email to variablestar@popastro.com

Thanks

Dave