The NGC 2467 Region

[AusGuy]

On 1^st April I viewed a few objects including this one in Puppis (the Stern Deck part of the old broken-up constellation of Argo Navis). At the time it did not seem worthwhile posting the result here, the nebula at first being somewhat underwhelming. But it's an interesting region and I thought that it might be worthwhile to see what a little brightening with Photoshop could achieve. Usually when the NGC 2467 region is displayed in amateur images on the internet you'll find that the total integrated time totals a few hours. This one was 4 minutes (4 x 60 seconds livestack). So there is a big difference in quality and detail. Nevertheless the brightened EAA view does show the basics.

The central section is an active star forming region of which the brightest part (NGC 2467) clearly shows an ionised HII stellar nursery. Most articles on the internet say that the main contributor to this red emission nebula is the massive O6 star HD64315 which is lost in the bright area circled in the annotated image. However a recent (2017) analysis concludes that that may not in fact be the case. It finds that the star is a multiple star containing at least two binaries with a likely total mass over 90 times that of the Sun and that it was formed without an accompanying cluster. So, on that basis, it is not part of NGC 2467. Who to believe? All sources agree that the two star clusters Haffner 18 and Haffner 19 are not immediately associated with NGC 2467 being just line of sight objects. 1 million years old Haffner 18 contains about 50 stars some of which are massive but short lived. Haffner 19 is a compact cluster with a Strömgren sphere (like the Rosette Nebula) where the cluster is surrounded by an ionised HII region. Its age is estimated at 2 million light years and yet Wikipedia says that the two clusters may be considered to be a binary cluster. Go figure.

You would think that it would be an easy internet search to find the distances to NGC 2467 and the two Haffner clusters but not so.

The ESO puts the nebula at 13,000 light years but Simbad says 1,355 parsecs (i.e. 4,422 light years). Wikipedia quotes both 4,420 and 20,500 light years on the same page! Given its size in the image I'm more inclined to believe the smaller figure. As to the two clusters, the ESO says that Haffner 18 is between 25,000 and 30,000 light years away, Wikipedia says 19,200 light years and Simbad says 19,264. A SAO/NASA paper suggests that Haffners 18 and 19 lie at about the same distance at 22,500 light years (which might tie in with Wikipedia's reference to the two clusters being a binary cluster were it not for the age discrepancy). So at the very least it would seem that both clusters are much farther away than NGC 2467.

“HD 64568 is a hot, extremely massive main sequence blue-white star that is the prototype of the O3 V((f*)) spectral category.”

The bright star HD64455 is a foreground B8 IV subgiant. Its distance is somewhere between 1,300 and 4,000 light years. And, of course, the other brighter stars are foreground objects too including OR Puppis which at only 900 light years distance is an M7 variable star having a brightness range of 6.85 to 7.10.

The area is popularly known as the Skull and Crossbones Nebula but good luck finding out why from this image!

Vixen R200SS; SW AZ-EQ6 Pro unguided; ZWO ASI294MC Pro; Baader MPCC III; Bortle 4.5

SharpCap livestack 4 x 60 seconds at 400 gain

Edited June 27, 2021 by AusGuy

[Adreneline]

30 minutes ago, AusGuy said:

This one was 4 minutes

An amazing result for just four minutes.

Thanks for sharing.

 

[Sunshine]

Nicely done!

[callisto]

I love to see images taken from the other side of our marble...thanks for posting 

 

Mark

[Marvin Jenkins]

Brilliant. What a well researched and thought out write up. I am impressed and interested in equal amounts. I hope to have a southern visit in a couple of years as my brother lives in Melbourne and has become a citizen.

It will undoubtedly be odd to look at the night sky and not recognise anything.

Marv

[AusGuy]

Thanks to all for your positive feedback. Apologies for the delay in posting this. Problem with computer connection.

Edited July 31, 2021 by AusGuy