The joy of Sigma Orionis

[Barry-W-Fenner]

Hi All,

Hope you are keeping well.

I managed a brief half hour last night for the first time since December due to the poor weather & a busy schedule!

The sky was as dark the darkest I have seen in a long time, A great contrast with the white snow covering the ground.

A look at the Seven Sisters with the 17.5mm Morph is always a joy to view.

I decided to have a look around Orion with my 9mm at x167 - The Nebula was simply stunning , lots of detail showing in a greyish Green colour.

After this I decided to head up to the belt area and started just below on Sigma Orionis,To my surprise I could see a system of 4 stars. This made me literally say "wow" out loud to myself. How could I have never seen this spectacular  set of stars?! I guess last winter I spent to much time on the usual suspects around Orion to even notice! I came away from the eye piece to lookup Sigma Orionis on Sky Safari, After a read up I learnt that it actually has 5 stars in this system. I went to hunt down the 5th and observe the different colours but to my horror the sky had been consumed in cloud while I was having a read up! 

This is going to be one of my 1st targets new time out, I would like to spend a bit more time studying this stunning system!

Regards

Baz

[John]

Nice report on a lovely target Baz

[Jiggy 67]

2 hours ago, Barry-W-Fenner said:

After this I decided to head up to the belt area and started just below

......careful 🤣🤣

Sigma Orionis is lovely, I’ve never got a fifth star though. Did you spot the binary, HD 294272 in the same field of view even at high magnification ?

[Barry-W-Fenner]

19 minutes ago, Jiggy 67 said:

......careful 🤣🤣

Sigma Orionis is lovely, I’ve never got a fifth star though. Did you spot the binary, HD 294272 in the same field of view even at high magnification ?

😂😂😂 That does sound a bit wrong doesn't it.

I didn't get to see the binary in the same FOV. To be honest I spent more time reading about it and lost the opportunity to observe as the cloud snuck up on me. I will most certainly have a longer study next time 👍

[Nik271]

9 minutes ago, Jiggy 67 said:

......careful 🤣🤣

Sigma Orionis is lovely, I’ve never got a fifth star though. Did you spot the binary, HD 294272 in the same field of view even at high magnification ?

The fifth star B is actually a close companion of the brightest star A, at a separation of 0.3 arcseconds. I doubt many people have the monster scope and seeing to see it at the eyepiece. Perhaps it can be imaged.

Actually the main star Aa has another super close companion Ab at separation .007 arcseconds currently. They complete an orbit each other in just 143 days! So there are in fact six stars in the system but with  <1 meter aperture equipment we can only see 4. 

[Barry-W-Fenner]

So I did OK then just seeing the 4 stars!  It's likely that I won't see anymore when I have a longer session with this system?

 

[Jiggy 67]

1 minute ago, Barry-W-Fenner said:

So I did OK then just seeing the 4 stars!  It's likely that I won't see anymore when I have a longer session with this system?

 

Always worth a re-visit. I’ve had the second binary in the same fov with a 4.5mm Morpheus, it’s easily split, at 2 o’clock

 

[Nik271]

1 minute ago, Barry-W-Fenner said:

So I did OK then just seeing the 4 stars!  It's likely that I won't see anymore when I have a longer session with this system?

 

You won't see more than the 4 stars, but it's worth revisiting again to check the nearby Struve 761, you will notice a pair of close stars and then a third star nearby in the same field of view as Sigma Orionis, as @Jiggy 67  suggested. This is another gravitationally bound pair but they haven't moved very much since they were first observed.  

[Stu]

Nice one @Barry-W-Fenner. A favourite of mine, and one I looked at last night. I even managed a smartphone image which just about captured the faint fourth star. The triple nearby is very nice too. The visual view way lovely last night, much better than my rubbish image!

As others have said, the fifth star is too close to be visible unless with a monster scope under rock steady seeing, at altitude, in a desert.... 🤣🤣

[Pixies]

Had a look tonight, but the poor transparency here, meant there was no sign of the 4th component.

The trapezium was stubbornly 4 stars, too.

[Voyager 3]

12 hours ago, Stu said:

Nice one @Barry-W-Fenner. A favourite of mine, and one I looked at last night. I even managed a smartphone image which just about captured the faint fourth star. The triple nearby is very nice too. The visual view way lovely last night, much better than my rubbish image!

As others have said, the fifth star is too close to be visible unless with a monster scope under rock steady seeing, at altitude, in a desert.... 🤣🤣

Is that with your 8" dob Stu ? 

[Merlin]

The Sigma System  has been likened to a miniature solar system. Infra red images of the system show it to contain over 300 brown dwarfs

[Merlin]

The figure of 300 brown dwarfs in the young star cluster might have been revised since I saw an infra red image some years ago, showing the cluster peppered with the dwarfs.

[John]

I often use the visiblity, or otherwise, of the 4th star in Sigma as an indicator of whether the E & F Trapezium stars might be visible.

 

[Barry-W-Fenner]

20 hours ago, Stu said:

Nice one @Barry-W-Fenner. A favourite of mine, and one I looked at last night. I even managed a smartphone image which just about captured the faint fourth star. The triple nearby is very nice too. The visual view way lovely last night, much better than my rubbish image!

As others have said, the fifth star is too close to be visible unless with a monster scope under rock steady seeing, at altitude, in a desert.... 🤣🤣

That is a fantastic shot Stu. You have managed to capture all these "tiny" suns with a simple smartphone camera!

 

 

[Stu]

11 hours ago, Voyager 3 said:

Is that with your 8" dob Stu ? 

Yes it was. The fourth star was very clear with it, nice. It’s not hard in a decent scope, even a 4” frac will show it.

[Stu]

4 hours ago, John said:

I often use the visiblity, or otherwise, of the 4th star in Sigma as an indicator of whether the E & F Trapezium stars might be visible.

 

That’s quite logical John, although it didn’t work for me this time. E was really quite obvious but F was only fleeting, if at all. Pesky little blighter it is! 🤣