Jump to content

sgl_imaging_challenge_2021_2.thumb.jpg.72789c04780d7659f5b63ea05534a956.jpg

40 Eridani - a great triple!


Recommended Posts

I've seen the Omicron2 white dwarf in a Prinz 60mm/f.11 refractor some years ago; it was more obvious with averted vision. The White dwarf orbits the red dwarf in 240 years and the pair orbit the primary in 8000 years. There' s all the time in the world in astronomy.

As you say, this is an interesting trio, showing three stars in different stages of stellar evolution.

  • Like 1
Link to post
Share on other sites
  • Replies 38
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

Just to say for those of you who like a target  which is not only interesting visualy but also contains a great deal of science behind it then this is the triple for you! The main mag 4.4 star is sun

This is 40 Eridani is probably my favorite multiple system, and the only one I can think in which a yellow dwarf, a white dwarf and a red dwarf can be observed together in a smallish scope. An in

SkySafari lists the main star Keid's alternative name as ........you guessed it..... Vulcan ?

Posted Images

  • 3 weeks later...

I'll have to revisit this one, the last time I looked was in the early 2000s with a 8" SCT.  Sadly the murk was a little too thick so I couldn't catch the red dwarf, I was very happy with seeing my first white dwarf though. 

  • Like 1
Link to post
Share on other sites

I've put this on my list, in case we ever get another clear night here! 😀

Astonishing that the white dwarf can be seen at all - it is 16 light years away and only about twice the diameter of the Earth!

  • Like 1
Link to post
Share on other sites
17 minutes ago, Captain Magenta said:

... looked up White Dwarf on Wiki. Discovered that Sirius B is also a White Dwarf. Makes my mission to observe it for the first time all that much richer...

M

Apparently, Sirius B is a little smaller than the Earth but it's mass is very nearly that of the Sun !

 

 

 

  • Like 2
Link to post
Share on other sites
On 24/12/2020 at 20:02, Hyperion76 said:

very interesting triple I often bump this topic 

Thanks for the bump, I wouldn't have known about it otherwise. Now just need some clear skies.

  • Like 1
Link to post
Share on other sites
  • 2 weeks later...

Yes, a very good bump. Reminded me to have a look at this again after many years. I must have forgotten the significance of this triple, so I slewed the scope over to it last night and had a good look. Amazing to think how small that white dwarf actually is and what distance we are observing it. It probably took me a while to learn about this star as it doesn't get a mention in what was for me 'the bible' of observing back in the early 70s, Patrick Moore's 'The complete Amateur  astronomer'. Odd really as he does talk about white dwarfs and mentions this triple in the constellation guide at the back of the book, but fails to mention it. It was the first to be observed, and its relatively easy with modest scopes. And one of the largest super earths known was found to be orbiting eridani A back in 2018, a great target, and a well timed bump. 

Edited by skyhog
spelling!
  • Like 3
Link to post
Share on other sites

Wow, I've found it. I couldn't find it last night and after many attempts I saw it tonight. Rigel is just too far to star-hop confidently from. The white dwarf was clear but it took me quite a while before I could hold it in direct vision. I tried 50x, 90x and 150x but couldn't be sure about the red dwarf. I had a little look at Orion and came back with my Vixen plossl. It shouldn't be better than my BCO but it did the trick at 90x. I'm really pleased. A tough challenge for me but so rewarding.

Thanks to everyone who has contributed to this thread. This is what SGL is all about. I wouldn't have known anything about it without this thread.

  • Like 4
Link to post
Share on other sites

I'm pleased to report that I managed to see the three stars in 40 Eridani last night.

The seeing started excellent and around 6:30pm I could even make the E and F stars of the Trapezium: E with direct vision and F with averted.

I was using a 180mm Mak with 20mm EP giving x135.

So I pointed at 40 Eridani and the white dwarf (B) was immediately obvious. With averted vision I could tell it was a double star. I put a towel over my head and dark adapted for 10 minutes, and was able to see the red dwarf (C) with direct vision! Very pleased about it, especially since the seeing went downhill from then on. 

I made this sketch from memory:

40Eridani.thumb.png.e58d1845bd05717b7f8bd5b09890e538.png

 

Thanks to all people who contributed to this thread, this is where I learned about this interesting triple star! 

  • Like 3
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.